Ultrastructure of cuticle deposited inPlodia interpunctella wing discs after variousβ-ecdysone treatments in vitro

Summary Wing discs of the Indian meal moth may be cultured for extended periods in vitro. The discs produced a tanned cuticle after continuous incubation with -ecdysone in medium conditioned with fat body or after a 24-h pulse incubation with -ecdysone in plain medium. We investigated the ultrastructure of the cuticle deposited by such discs. We found that the treatment that produced the most complete cuticle in vitro was the 24-h pulse of hormone. We observed that cuticle formation in vitro was not all-or-none. Depending on culture conditions, discs produced cuticulin only, complete epicuticle, epicuticle plus diffuse endocuticle, epicuticle plus lamellate endocuticle, or even multiple layers of cuticle. The ultrastructural evidence suggests that continuous incubation with -ecdysone in plain medium does not always inhibit cuticle formationper se, but does prevent tanning of the partially formed cuticle.     

Effects of short-term storage of gametes on fertilization of Pacific herring eggs

A method is described whereby arrays of samples ofClupea pallasi eggs may be stored during their preparation. The high fertilization potential retained by the eggs during short-term storage allows them to be fertilized synchronously when sample preparation is complete. A variation of the dry method of storage retained maximum fertilization potential (80–85%) of the eggs for about 1 hr, and of milt dilution (18 with 17 S sea water), about 7 hr. Following dry storage, eggs fertilized in salinities of 0–45 showed maximum rates of fertilization in salinities of 10–20, and fertilization rates 50% in salinities of 4.5–42. Salinities of fertilization influenced egg diameter, median hatching time, and larval length at hatching in egg samples transferred 21/2 hr after fertilization to an incubation salinity of 17 at 7°C. Fertilization rates were higher (90–95%) for eggs stored in 17 S at 7°C prior to fertilization. Under such wet storage conditions, maximum fertilization pontential was retained for about 2 hr. Highest fertilization rates (95–96%) were obtained for eggs stored and fertilized in salinities of 12–15. For the species and the area of origin considered (British Columbia), wet storage of eggs should result in maximum fertilization when the eggs are stored at 4°C for a period not greater than 2 hr prior to fertilization in the 12–15 S storage medium.Prepared under the auspices of the Canadian-German Scientific and Technical Cooperation Agreement.     

Zur Feinstruktur von Cuticula und Epidermis beim Flußkrebs Orconectes limosus während eines Häutungszyklus

Zusammenfassung Die Cuticula an der Innen- und Außenseite der Branchiostegite des Flußkrebses besteht wie für Arthropoden üblich aus Epi- und Procuticula. Sowohl die Epicuticula als auch die Procuticula von Innen- und Außenseite unterscheiden sich im Feinbau wesentlich voneinander. An der Innenseite ist die Epicuticula einfach gebaut; Die Procuticula ist lamelliert und zeigt meist die bogenförmigen Muster von Mikrofibrillen. Die Epicuticula an der Außenseite weist in den in dieser Arbeit untersuchten Entwicklungsstadien einen sehr viel komplizierteren Feinbau auf, der in der Entwicklung gewissen Änderungen unterliegt. In der wiederum lamellierten Procuticula an der Außenseite sind die Mikrofibrillen zu Balken gebündelt. Die Ausrichtung der Mikrofibrillen dreht sich innerhalb einer Lamelle um 180°. Durch die Procuticula ziehen Fortsätze der Epidermiszellen, außerdem Stäbe der sog. Verbindungsstrukturen.Die Bildung der Cuticula an der Innenseite konnte weitgehend vollständig verfolgt werden; sie ist gut mit der Bildung der Cuticula bei verschiedenen Insekten vergleichbar.Die Bildung der Cuticula an der Außenseite konnte dagegen nur von Beginn der Abscheidung der Proouticula bis zur Häutung verfolgt werden. Kurz vor Beginn der Cuticulaabscheidung kommt es in den Epidermiszellen zu einer stärkeren Entwicklung des rauhen ER. Während der gesamten von uns verfolgten Bildungsstadien sieht man Vesikel mit dichtem Inhalt besonders in der Nähe des Zellapex. Sie geben anscheinend hier ihren Inhalt, Cuticulamaterial, nach außen ab. Sie stammen wohl aus Golgibereichen. Auch Stachelsaumbläschen (coated vesicles) kommen regelmäßig vor, deren genetischer Zusammenhang mit multivesikulären Körpern diskutiert wird. Bei der Abscheidung der fibrillären Cuticulasubstanzen spielen besondere Differenzierungen der Zell oberfläche, — kappenartige Verdichtungen der Zelloberfläche, meist an der Spitze kleiner Mikrovilli — eine wesentliche Rolle.

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The ultrastructure of cuticle and epidermis in the crayfish Crconectes limosus during a moulting cycle

Summary The cuticle of the inside and outside of the branchiostegites of the crayfish consists of an epicuticle and a procuticle — as common in arthropods. Concerning their ultrastructure epicuticle and procuticle differ essentially from each other on both the inside as well as the outside. On the inside the epicuticle is built plainly; the procuticle is laminated, and, mostly it shows the arched patterns of microfibrils. In those developmental stages investigated in this project the epicuticle of the outside shows a much more intricated ultrastructure, since during formation it is subject to certain changes. On the outside the procuticle is also laminated; the microfibrils are bundled up to bars. The alignment of those microfibrils within one lamella is twisted for 180°. The procuticle is penetrated by processes of epidermal cells and by rods of the so-called connecting structures.The formation of the cuticle on the inside was observed completely; it is comparable to the forming of the cuticle in several insects. However, the formation of the cuticle on the outside was only observed from the beginning of the procuticular development up to the moulting.Shortly before formation of the cuticle the development of rough ER in the epidermal cells seems to be intensified. In all of developmental stages observed there appear vesicles with dense contents mainly situated nearby the cell apex. At this site they evidently deliver their contents — cuticular materials — to the outside of the cell; they probably originate in the Golgi areas. There occur coated vesicles regularity, too; their genetic relation to multivesicular bodies is discussed. Special differentiation on the cell surface i.e. dome-like consolidations of the cell surface mainly placed at the tip of small microvilli are of great importance for the secretion of the cuticle substances.

     

Polysaccharide and protein secretion by grass microhairs

Summary Secretory activities of bicellular microhairs from grasses belonging to the subfamilies Chloridoideae, Arundinoideae, Panicoideae, and Bambusoideae, and including the chloridoid, panicoid and Enneapogon microhair morphological types, have been investigated. Light microscopic histochemistry indicated that all microhairs studied secrete polysaccharide and protein (or glycoprotein), including those which also secrete salt. Localization of polysaccharide at ultrastructural level using periodic acid-thiocarbohydrazidesilver proteinate staining revealed that in panicoid type microhairs dictyosomes are involved in polysaccharide secretion, whereas in the chloridoid and Enneapogon types partitioning membranes seem to be involved instead.Abbreviations Ag silver precipitates representing localization of polysaccharide - BC basal cell - C cuticle - CC cap cell - CH cuticular chamber - CN system of membrane bound channels and vesicles - CP chloroplast - CW cell wall - D dictyosomes - M mitochondria - N nucleus - PTM partitioning membranes - RER rough endoplasmic reticulum - S secretory material - St starch grain - US unstained dictyosome cisternae - V vesicle     

Growth and Reproduction of Double-Ended Pipefish, Syngnathoides biaculeatus, in Moreton Bay, Queensland, Australia

Life-history characteristics of the double-ended pipefish, Syngnathoides biaculeatus (Bloch), were investigated to determine growth rate, degree of sexual dimorphism, size at maturity, and reproductive biology. Growth rates of wild juveniles and adults calculated from monthly progression of length-frequency modes ranged from 0.8mmd^–1 (fish lengths 120–145mm standard length (SL)) in summer to 0.2mmd^–1 in winter (185–200mm SL). Growth of laboratory-reared juveniles up to 63d old was greater, ranging from 0.8 to 2.3mmd^-1. The von Bertalanffy growth constant K was estimated at 0.0076d^{- 1}, or 2.8year^–1. Morphological differentiation between the sexes based upon abdominal pattern was possible for fish larger than 120mm SL, with females possessing a zigzag pattern on the abdomen. The association between this pattern and sex was confirmed by histological gonad analysis. Males were significantly longer than females during four of seven seasons examined, and a 1:1 sex ratio was determined for all seasons except autumn when the ratio was female biased. The breeding season was marked by the appearance of pregnant males between October and April, and during courtship both species exhibited increased pigmentation. The minimum paternal size at maturity was 185mm, the maximum length recorded 260mm. Clutch size ranged between 60 and 200 eggs, with a mean of 153. Ovaries had a sequential pattern of egg development, resulting in egg batches that approximated the number of eggs carried by brooding males. Additionally, all eggs in a brood were at the same developmental stage. This suggests that one female provides all of the eggs for one male per breeding event in a monogamous mating system.     

Sequence analysis of the upstream regions of Xenopus laevis β-globin genes and arrangement of repetitive elements within the globin gene clusters

The globin gene clusters of Xenopus laevis are interspersed by various different repetitive DNA elements. A specific repeat, the JH12 element, has been mapped by Southern analysis and some of its locations have been subsequently confirmed by nucleotide sequencing. JH12 family members seem to represent mobile genetic elements and display a high degree of divergence. The nucleotide sequences upstream to the adult _I-globin gene and to the two coordinately expressed larval _I- and _II genes have been determined and compared to those of the adult -genes. Besides some repetitive DNA elements and a short sequence of rather weak homology we have found no characteristic sequence motifs to be common to the adult - and -genes. The two larval -genes share one short sequence element being absent from the adult genes. This might reflect completely different sequence requirements for protein interactions and for the regulation of adult and larval globin gene expression.     

Intraorbital cerebrospinal fluid outflow and the posterior uveal compartment of the hamster eye

Summary An ultrastructural and tracer study was undertaken to determine normal outflow pathways of cerebrospinal fluid (CSF) at the terminal subarachnoid space (SAS) of the optic nerve. In the morphological studies, the optic nerve dura and arachnoid were found to be continuous with the sclera of the eye beyond the optic nerve SAS. The pia mater is continuous with the inner sciera and the lamina fusca of the eye. Montages and serial sections demonstrated that the distal SAS is divided into numerous tortuous channels to form an arachnoidal trabecular meshwork. Spaces of this meshwork continue into microcanals which bypass the outer arachnoid barrier layers of the optic nerve meninges to reach the sclera and posterior intraorbital connective tissue. Ferritin infused into the cisterna magna entered the optic nerve SAS within 1 min and reached arachnoidal trabecular meshwork channels and the microcanals within 8 min. It then passed into intraorbital connective tissue spaces at the posterior pole of the eye. Ferritin appeared to be blocked by the lamina fusca and a newly discovered posterior compact zone which together prevented its entrance into the choroidal interstitium. These observations suggest that a subarachnoidal-scleral-orbital outflow pathway provides a route for CSF drainage from the optic nerve SAS to intraorbital connective tissue. The previously described posterior uveal compartment in the hamster eye (Kelly et al. 1983) appears to be relatively isolated from this subarachnoidal-scleral-orbital CSF outflow.Parts of this work have been presented at the 1984 meetings of the American Association of Anatomists (Shen 1984).     

Osmotic measurements on stomatal cells ofCommelina communis L.

Summary Observations of aperture changes as sucrose is added to the solution bathing epidermal strips ofCommelina communis L. allow calculation of the osmotic changes required to open or close the stomatal pore, for comparison with changes in potassium content. With isolated guard cells, in strips in which all cells other than guard cells have been killed, the internal osmotic changes required are 83 mosmol kg^–1 m^–1 below 10m aperture, 129 mosmol kg^–1 m^–1 in the range 10–15 m, and 180 mosmol kg^–1 m^–1 above 15 m. For opening against subsidiary cell turgor in addition to guard cell turgor, in intact strips with live subsidiary and epidermal cells, these figures should each be increased by about 33 mosmol kg^–1 m^–1. A change in subsidiary cell turgor is magnified in its effects on the water relations of the guard cell by a factor greater than 3.7 for equal changes in the water potential of the two cells, or greater than 4.7 at constant volume of the guard cell.     

Alarm response of hatchlings of the apple snail, <Emphasis Type="Italic">Pomacea canaliculata</Emphasis> (Gastropoda: Ampullariidae), to aqueous extracts of other individuals

We examined how hatchlings of the freshwater snail, Pomacea canaliculata, responded to aqueous extracts of conspecific hatchlings. Three, 3-day-old hatchlings were macerated in deionized water (1mg hatchling per 1ml water). When 0.5ml of the aqueous extract was added to a test tube containing 10 hatchlings of the same age and 50ml of water, the hatchlings in the water began to crawl out of the water within 5min. The proportion of hatchlings that crawled out of the water approached 0.6–0.9 after 1h, but gradually decreased to 0.4 after 24h. The relatedness between the live and the macerated hatchlings had no significant influence on the response. Hatchlings of egg masses obtained either in the laboratory or in the wild responded similarly to aqueous extracts of hatchlings from either egg mass. This suggests that the conditions under which the egg masses were incubated or the conditions that their parents had experienced had no effect on the hatchlings response. When compared with experiments reported on other aquatic animals, we consider the behavior of the hatchlings to be an alarm response of escaping from predators.     

Comparative residual toxicities of pesticides to the predator Agistemus industani (Acari: Stigmaeidae) on citrus in Florida

Residual toxicities of registered and selected experimental pesticides used on citrus against Agistemus industani Gonzalez (Acari: Stigmaeidae) were compared. Pesticides considered highly toxic to A. industani were: abamectin 0.15 EC at 731ml/ha+FC 435-66 petroleum oil at 46.8l/ha, pyridaben 75WP at 469g/ha, ethion 4EC at 7.01l/ha+FC 435-66 petroleum oil at 46.8l/ha, propargite 6.55 EC at 3.51l/ha, chlorfenapyr 2SC at 1.46l/ha applied alone or in combination with FC 435-66 petroleum oil at 46.8l/ha, sulphur 80DF at 16.81kg/ha, dicofol 4EC at 7.01l/ha, fenbutatin oxide 50WP at 2.24kg/ha, benomyl 50WP at 2.24kg/ha, benomyl 50WP at 1.68kg/ha+ferbam 76 GF at 5.60kg/ha, ferbam 76GF at 11.21kg/ha, neem oil 90EC at 46.8l/ha, and copper hydroxide DF (40% metallic copper) at 4.48kg metallic copper/ha+FC 435-66 petroleum oil at 46.8l/ha. Pesticides that were moderately to slightly toxic included: copper sulphate 98% at 4.48kg metallic copper/ha+FC 435-66 petroleum oil at 46.8l/ha, fenbuconazole 2F at 280ml/ha+FC 435-66 petroleum oil at 46.8l/ha, FC 435-66 petroleum oil applied alone at 46.8l/ha or 23.4l/ha, and diflubenzuron 25WP at 1.40kg/ha. Pesticides that were non-toxic included: fenbuconazole 2F at 585ml/ha, malathion 57EC at 5.85l/ha, FC 435-66 petroleum oil at 46.8l/ha, carbaryl 80S at 3.36kg/ha, chlorpyrifos 4EC at 4.68l/ha, and formetanate 92SP at 1.12kg/ha. Understanding the toxic effects of field weathered pesticides against key predacious mite species is important for effective IPM. The results of this study provide a comparison of direct and indirect toxic effects of various pesticides to A. industani under field conditions.     

Transmission of plastids by pollen in Antirrhinum majus

Summary Up to now Antirrhinum was classified as a typical example for a uniparentalmaternal inheritance of the plastids. However, the findings reported here prove that also the male gametophyte of Antirrhinum may occasionally transmit plastids into the egg. This conclusion is based on genetic experiments involving a form of the plastom mutant prasinizans which is described as gelbgrüne prasinizans. In contrast to all other plastid mutations known in Antirrhinum majus this mutant originated in Sippe 50 is completely viable. In plants containing plastids of this mutant type only, the mutant character is manifested during early growth stages. Cotyledons and first foliage leaves which are initially white or white yellow, slowly turn green and become indistinguishable from normal Sippe 50. Reciprocal crosses of green Sippe 50 with gelbgrüne prasinizans gave few variegated descendants; the others were exclusively plants identical with the maternal parent as far as leaf colour is concerned (Table). The variegated individuals cannot be gene mutants since selfing and crossing experiments showed non-mendelian inheritance. Furthermore it could be ruled out that in the cross Sippe 50 x gelbgrüne prasinizans the three variegated descendants represent spontaneous new plastom mutants because the pale tissue in these plants turned green in the same way as the paternal parent. Because of the typical greening of this mutant and since plastid mutations could be ruled out we have to conclude that plastids were transmitted by the pollen parent into the egg. There these plastids multiplied together with the maternal plastids giving rise to the chimeras after sorting-out of the two plastid types. This interpretation is supported by the observation of mixed cells in tissues where the leaf variegation is finely mosaiced. The results were possible only because the plastids of the pollen parent can be unequivocally recognised.     

Binding of the galactose-specificPseudomonas aeruginosa lectin,PA-I,to glycosphingolipids and other glycoconjugates

The carbohydrate-binding specificity ofPseudomonas aeruginosa lectin I (PA-I) in iodinated or biotinylated form was studied. A large number of glycosphingolipids, as well as some glycoproteins and neoglycoproteins were used as ligands. Also, inhibition by free saccharides of PA-I binding to glycosphingolipids was tested. It was found that the lectin binds most strongly to terminal and nonsubstituted Gal3Gal- or Gal4Gal-structures.Abbreviations PA-I Pseudomonas aeruginosa lectin I - Cer ceramide - lactosylceramide Gal4GlcCer - iso globotriaosylcerami Gal3Gal4GlcCer - globotriaosylceramide Gal4Gal4GlcCer - globoside or globotetraosylceramide GalNAc3Gal4Gal4GlcCer - Forssman glycolipid GalNAc3GalNAc3Gal4Gal4GlcCer - P1 glycolipid Gal4Gal4GlcNAc3Gal4GlcCer - lactoneotetraosylceramide Gal4GlcNAc3Gal4GlcCer - B5 glycolipid Gal3Gal4GlcNAc3Gal4GlcCer - gangliotetraosylceramide Gal3GalNAc4Gal4GlcCer - GM1 Gal3GalNAc4(NeuAc3)Gal4GlcCer - RBC red blood cells - BSA bovine serum albumin - PBS phosphate-buffered saline - SDS sodium dodecyl sulfate - TLC thin-layer chromatography - HPLC high pressure liquid chromatography - MS mass spectrometry - FAB fast-atom bombardment - EI electron impact     

Revêtement cuticulaire de la gaine de la trompe chez Glycera convoluta Keferstein (Annélide Polychète)

Résumé Il existe trois types différents de cuticule dans la gaine de la trompe de Glycera convoluta. La cuticule banale, entre les papilles, est formée de collagène. La cuticule amincie de la face antérieure de la papille est pauvre en fibres de collagène et traversée par de nombreuses microvillosités revêtues à leur surface d'un abondant glycocalyx. La cuticule de la face postérieure portant l'onglet est épaissie et superficiellement kératinisée. Etude histochimique et ultrastructurale.

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Cuticle of the proboscidian sheath in Glycera convoluta keferstein (Annelida, Polychæta)Histochimie et ultrastructure

Summary There are three types of cuticles in the proboscidian sheath of Glycera convoluta. The common cuticle, between the papillae, is made up with collagen. The slimmed cuticle of the fore side of the papilla contains no more collagen fibers; it is crossed by numerous microvilli, the external surface of which is covered with a well developed cell-coat. The cuticle of the hinder side, which bears the onglet, is thickened and keratinized. Histochemical and ultrastructural study.

     

Untersuchungen über die Ultrastruktur der Gonaden von Chironomus (Dipt.)

Zusammenfassung Im Ovar von Chironomus sind in Phase 1 des 4. Larvenstadiums polygonal abgeflachte Innenzellen von kleineren Außenzellen umgeben, die Bakteroide und Phagosomen enthalten; zwischen den Innenzellen liegen unregelmäßige Zelltrümmer (keimbahnbegleitende Substanzen). Zu Beginn der Ovariolenbildung werden in Phase 3 durch Spalträume zwei Schichten der Außenzellen voneinander getrennt, von denen die innere (Follikel- und Eikanalepithel) regelmäßige Buchten bildet. In diese Buchten wandern von innen Zellpaare ein, die an synaptischen Komplexen bzw. multiplen Chromatinstrukturen als Ei- und Nährzellen kenntlich sind. Zwischen beiden Zellen sind Fusome häufig, die später in eigentümlicher Weise geschlossen werden. Zwischen den Eikanalzellen entsteht in Phase 5 durch Spaltbildung der Eikanal; in Phase 7 sind die Eikanalzellen auffallend glykogenreich. Kurz vor der Vitellogenese treten im Bereich der Oocyte Membransysteme und annulated lamellae auf; akzessorische Kerne werden als Ausstülpungen des Oocytenkernes gebildet und später abgeschnürt. In Phase 9 sind an der Peripherie der Eizelle Mikrovillisäume und Pinocytosebläschen sichtbar. Die distalen Zellen der Ovariole haben Eioder Nährzellcharakter, sind aber bei Ch. melanotus nicht von Follikelzellen umgeben und werden beim weiteren Ovariolenwachstum reduziert. Trotz extrem geringer Nährzellzahl der Follikel scheint das Chironomus-Ovar funktionell nicht von anderen polytroph meroistischen Insektenovarien unterschieden.

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Ultrastructure of Chironomus (Dipt.) gonads1. Normal development of ovaries during the fourth larval instar

Summary In the ovary of Chironomus during phase 1 of the fourth larval instar, polygonally flattened inner cells are surrounded by smaller outer cells which contain bacteroids and phagosomes. Irregular cell remnants (germ line accompanying substances) lie among the inner cells. At the beginning of ovariole formation in phase 3, two layers of outer cells are separated by the formation of fissures. The inner layer of these cells (follicle- and egg-passage epithelium) forms regular invaginations. Cell pairs, identified as oocytes and nurse cells by synaptic complexes or multiple chromatin structures, wander from inside into the invaginations. Frequently between the two cells are fusomes, which later close in a characteristic manner. During phase 5, an egg passage is formed as a fissure among the egg-passage cells. During phase 7, the egg passage cells are conspicuously full of glycogen. Shortly before vitellogenesis membrane systems and annulated lamellae appear in the region of the oocyte. Accessory nuclei are formed by a tieing-off of projections of the the oocyte nucleus. During phase 9, microvilli and pinocytotic vesicles can be seen at the periphery of the oocyte. The distal cells of the ovariole are of oocyte or nurse cell nature, but in Ch. melanotus they are not surrounded by follicle cells and are reduced during further ovariole growth. In spite of the extremely small number of nurse cells in the follicle, the Chironomus ovary apparently does not differ functionally from other polytrophic meroistic insect ovaries.

Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Large scale preparation of PA-oligosaccharides from glycoproteins using an improved extraction method

We have developed a new method for the large scale preparation of pyridylaminated (PA-) oligosaccharides from glycoproteins. Phenol/chloroform extration was adapted for the removal of protein and excess 2-aminopyridine, improving the efficiency of preparation. From a 2.5 g sample of human apo-transferrin, 25–30 mol of agalacto biantennary PA-oligosaccharide could be obtained. By increasing the concentration of PA-oligosaccharide substrate, we were able to detect a very low level ofN-acetylglucosaminlytransferase IV activity in CHO cell extracts.Abbreviations PA 2-aminopyridine - SDS sodium dodecyl sulfate - GlcNAc N-acetylglucosamine - GnT N-acetylglucosaminyltransferase - Gn,Gn-bi-PA GlcNAc1-2Man1-3(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc-2-aminopyridine - Gn,Gn,Gn-tri-PA GlcNAc1-2(GlcNAc1-4)Man1-3(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc-2-aminopyridine - Gn,Gn,Gn-trí-PA GlcNAc1-2Man1-3({GlcNAc1-2(GlcNAc1-6)Man1-6})Man1-4GlcNac1-4GlcNAc-2-aminopyridine - Gn,(Gn),Gn-bi-PA GlcNAc1-2Man1-3(GlcNAc1-4)(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc-2-aminopyridine     

Adoptions expérimentales de larves entre des fourmis de genres différents:Leptothorax nylanderi Förster etSolenopsis fugax Latreille

Résumé En l'absence de son propre couvain,Solenopsis fugax a élevé des larves deLeptothorax nylanderi, à la température de 22°C. Les ouvrières deSolenopsis détruisirent une partie de ces larves mais nourrirent celles qu'elles épargnèrent; ces dernières grossirent lentement pendant cinq à six mois, sans atteindre le stade prénymphe. Lorsque les ouvrières deS. fugax et les larves deL. nylanderi furent soumises ensemble à un hivernage préalable, elles donnèrent les mêmes résultats que sans hivernage. La présence d'une jeune reine deSolenopsis fut défavorable aux larves deLeptothorax.Inversement,L. nylanderi fut capable d'élever, à la température de 22°C, des larves deS. fugax et de les amener jusqu'au stade adulte. En présence de leurs propres larves, les ouvrières deL. nylanderi détruisirent tapidement toutes les larves deS. fugax introduites dans leur nid. D'autre part, un jeune couvain deLeptothorax remplaçait plus ou moins rapidement les larves deLeptothorax enlevées au préalable; sa présence était alors défavorable au développement des larves deSolenopsis. Un hivernage en début d'expérience fut plutôt favorable auxS. fugax, de même que la présence d'une reine féconde deLeptothorax. LesSolenopsis ainsi obtenus n'ont pas vécu plus de sept semaines. Ils étaient tous de caste ouvrière et de taille très petite.

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Summary When its own eggs and larvae missed,Solenopsis fugax bred larvae ofLeptothorax nylanderi, at a temperature of 22°C. TheSolenopsis workers killed some of this larvae and fed the others; these slowly grew bigger during five or six months but never reached the pre-pupa stage. The result was the same if the workers ofS. fugax and the larvae ofL. nylanderi overwintered together or not at all. A youngSolenopsis queen being there was noxious to the larvae ofLeptothorax.On the contrary,L. nylanderi has been able to breed larvae ofS. fugax up to the imago stage, at a temperature of 22°C. When its own larvae were in the nest, together with larvae ofS. fugax, the workers ofL. nylanderi killed the larvae ofS. fugax. On the other hand, new eggs and young larvae ofLeptothorax had to replace, more or less quickly, the larvae which had been taken away, and that was noxious to the growth ofSolenopsis larvae. An overwintering at the beginning of the experiment was rather favourable toS. fugax as was the presence of a fecundLeptothorax queen. TheSolenopsis thus obtained lived no longer than seven weeks. They all were workers and very small.

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S. Fugax L. Nylanderi 22° . Leptothorax , , , , . . S. Fugax Leptothorax.,L. Nylanderi 22° S. Fugax . L. Nylanderi ( )Leptothorax ; S. Fugax Solenopsis, Leptothorax. S. Fugax . .

     

Das organische Gerüstwerk der Kalkschale des Schwanen-Eies

Zusammenfassung Kegel und Säulen der Schwanen-Eischale hinterlassen am Querschliff nach Entkalkung mit EDTA organisches (mucoproteides) Material als ein zusammenhängendes Gerüst, das sich mit Thionin metachromatisch färbt; ohne Demineralisierung oder wenigstens Anätzung bleibt Thionin an Schliffen und Bruchkanten der Schale wirkungslos. Das Lichtmikroskop zeigt an Schliffen nichts von dem organischen Material, es wurde während des Kristallwachstums fein zerteilt in Gitterlücken des Schalencalcits eingeschlossen. Es findet sich am stärksten angehäuft an den äueren und inneren Oberflächen der Kristall-individuen. In den Kegeln ist das Gerüst radial ausgebildet als die Loculi der Keile, und konzentrisch geschichtet, entsprechend den Lagen der Globularinklusionen, um deren jede herum Verdichtung der organischen Substanz statthat. In den inneren Säulen folgt das organische Gerüst dem Rhombenmuster; die äueren Säulen sind arm an organischer Substanz, hier verbleibt nach der Entkalkung eine dünne laterale Oberflächenschicht.

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Summary The cones and columns of the swans egg shell leave behind after decalcification with EDTA an organic (mucoproteid) material in form of a continuous frame work stainable metachromatically with thionine. Without demineralisation or at least etching, thionine proves ineffectual in ground sections or breaking edges of the shell. In ground sections the light microscope demonstrates nothing of the organic material: it was inclosed during the crystal growth in submicroscopical lattice gaps of the calcite individuals. The organic material is chiefly accumulated in the outer and inner surfaces of the crystals. In the cones the organic frame work is developed radially as the loculi of the wedges and concentrically layered corresponding with the globular inclusions, concentrated in the circumference of each. In the inner columns the organic material follows to the rhomb pattern. The outer columns after decalcification only leave behind a thin lateral organic sheath.

     

The relationships between the structure of paddy levees and the plant species diversity in cultural landscapes on the west side of Lake Biwa,Shiga, Japan

Paddy levees form networks of narrow linear habitats and play various roles in cultural landscapes. Traditional landscapes on the west side of Lake Biwa consist of paddy field terraces and both stone and soil levees that have been maintained by paddy field management using local resources. Paddy levees in this study site are principally classified into five different types. Our study points out how differences in paddy levee structure as well as in management practices influence the plant species. Seventeen paddy levee transects were split into four habitat types based on their species components by TWINSPAN. Spatial characteristics and physical structures of paddy levees depended on natural conditions and human activities. The species–area curves of each levee type showed a clear distinction: the soil, stone and abandoned curves were steep, while the concrete and consolidated ones were gentle. The vegetation on consolidated levees was utterly different from the vegetation on traditional levee types from the aspect of species richness and species components. Soil type levees contained various woody plant species and included more diverse and indigenous plant species than abandoned type levees.     

Role of bag cells in egg deposition ofAplysia brasiliana

Summary Egg deposition behaviors are analyzed from time-lapse recordings during which spontaneous discharges of the neuroendocrine bag cells are recorded with chronically implanted cuff electrodes. In the laboratory,Aplysia brasiliana normally deposit long egg cordons on the substrate in a characteristic figure 8 pattern similar to the configuration of egg masses observed in the natural environment. The overt behaviors associated with egg deposition are rhythmic head movements consisting of three components that overlap with characteristic relative latencies: up-and-down undulations, side-to-side weaves and in-and-out tamps. The characteristics of the three behaviors and their time courses relative to the appearance of eggs on the substrate suggest that undulations prepare the substrate, weaves distribute the egg cordon and tamps attach the cordon to the substrate. The same rhythmic head movements are also elicited by injections of homogenized abdominal ganglia (HAG) containing bag cell clusters, with comparable relative latencies and maximum frequencies but for shorter total durations. The overt behaviors begin earlier for normal than for triggered egg laying, often before the spontaneous release of bag cell hormones. This suggests that the head oscillations in intact animals are not normally initiated by bag cell activity. The mean latency to the appearance of the egg cordon on the substrate is the same (about 34 min) following either HAG injections or spontaneous bag cell discharges, confirming previous suggestions that the bag cell discharge triggers ovulation. Furthermore, the head movements appear to terminate at the same time following release or injection of hormone. The accompanying paper demonstrates that the full expression of the behavioral effects of bag cell injections depend upon normal movement of eggs in the reproductive tract.Abbreviations CPG central pattern generator - ELH egg laying hormone - HAG homogenized abdominal ganglia     

Descriptive morphology of the reared eggs,larvae, and juveniles of the marine atherinid fish <Emphasis Type="Italic">Atherinomorus duodecimalis</Emphasis>

Embryonic, larval, and juvenile development of the marine atherinid Atherinomorus duodecimalis are described from laboratory-reared specimens. The eggs, measuring 1.15–1.24mm in diameter, were demersal and almost spherical in shape with numerous chorionic filaments. Hatching occurred 7 or 8 days after spawning, the newly hatched larvae measuring 4.5–5.1mm in body length (BL) and having 5+34=39 myomeres. Notochord flexion started at 6.9mm BL and finished at 8.3mm BL. Aggregate numbers of all fin rays were completed by 14mm BL. Eggs of this species could be distinguished from other known atherinid eggs on the basis of egg diameter and the arrangement, length, and number of chorionic filaments. Larvae were also distinctive in myomere counts, pigmentation, and locations of the anus and second dorsal fin origin.