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1.
ABO, rhesus and Kell blood group data on 1327 donors in Kabul are analysed by ethnic affinity and compared with existing data on Afghanistan peoples. Blood group frequencies are very similar in Pushtu and Tadjik, despite their different historical, linguistic, and cultural backgrounds. Inclusion of the small sample of Hazara in the analysis shows overall heterogeneity in rhesus D, E, and e frequencies, suggesting the existence of a broader pattern of genetic variation among the peoples of Afghanistan.  相似文献   

2.
The coremata and male genital structures together with the associated muscles of Zygaena trifolii are described and illustrated in detail. Of the female genitalia only the external parts are dealt with. The closure of the male coremata pouch was found to be effected by a special muscle. Mating pairs were quickly fixed while in copula and dissected afterwards in order to examine the mechanism of copulation. It turns out that the female is held by the male at three points: first, the gonopods (= valvae) grip the female abdominal tip laterally. Secondly, the praephallus together with the everted endotheca (= vesica) are tightly locked inside the female ductus bursae. Thirdly, female postvaginal structures become evaginated and are then held between the spined anellus and the eighth abdominal tergum of the male.  相似文献   

3.
The cnidom of the sea anemone Sagartiogeton viduatus (Muller, 1776) is described from interference‐contrast light micrographs (LMs) and scanning electron micrographs (SEMs). Special attention is given to nematocyst maturation, including the differentiation of the shaft into proximal and main regions as helical folding of the shaft wall proceeds. Comparisons are made with Metridium senile (Linnaeus, 1761), whose cnidom, with a few exceptions, is closely similar to that of S. viduatus. The two anemones possess b‐ and p‐mastigophores, p‐amastigophores, isorhizas and spirocysts. Although the majority of cnidae in S. viduatus is smaller than corresponding ones in M. senile, they are grouped into the same size classes as those of M. senile, namely small, medium and large. The main differences from M. senile cnidae are the followings: (1) Large acontia p‐amastigophores are the largest nematocysts in S. viduatus. (2) They are noticeably larger than the large acontia b‐mastigophores, and (3) they are separated from the p‐amastigophores of M. senile by the sinusoid pattern of their U‐shaped capsular matrix. (4) The large acontia b‐mastigophores are microbasic and not mesobasic as in M. Senile, and (5) they do not produce darts. (6) Another difference from M. senile is the absence of catch‐tentacle isorhizas.  相似文献   

4.
Spermiogenesis of the syncarid Anaspides tasmaniae (subclass Eumalacostraca) was investigated by transmission electron microscopy. The spermatozoan of Anaspides is an ovoid cell with an acrosome covering the anterior pole and a lobulated nucleus and mitochondria occupying the rest of the cell. A long subacrosomal filament bypasses the nucleus and forms a spiral that supports a thin extension of the posterior cytoplasm, giving the spermatozoan a bell-shaped appearance. No flagellum is present at any stage. The immobile spermatozoans are embedded in a hard capsule, secreted by the cells of the wall of the vas deferens.  相似文献   

5.
基于馆藏标本的研究, 确认广东产3 种轴鳞蕨属植物: 异鳞轴鳞蕨Dryopsis heterolaena、泡鳞轴鳞蕨D. mariformis 和阔鳞轴鳞蕨D. maximowicziana , 其中泡鳞轴鳞蕨和阔鳞轴鳞蕨为广东新记录的蕨类。澄清广东不产顶果轴鳞蕨D. apiciflora , 最近出版的《广东植物志》第七卷记载的顶囊肋毛蕨Ctenitis apiciflora ( 即顶果轴鳞蕨D. apiciflora) , 系异鳞轴鳞蕨的错误鉴定。文中列有分种检索表、种的文献引证、标本引证、生境与分布资料。  相似文献   

6.
广东产轴鳞蕨属(叉蕨科)植物   总被引:2,自引:0,他引:2  
基于馆藏标本的研究,确认广东产3种轴鳞蕨属植物:异鳞轴鳞蕨Dryopsis heterolaena、泡鳞轴鳞蕨D·mariformis和阔鳞轴鳞蕨D·maximowicziana,其中泡鳞轴鳞蕨和阔鳞轴鳞蕨为广东新记录的蕨类。澄清广东不产顶果轴鳞蕨D·apiciflora,最近出版的《广东植物志》第七卷记载的顶囊肋毛蕨Ctenitis apiciflora(即顶果轴鳞蕨D·apiciflora) ,系异鳞轴鳞蕨的错误鉴定。文中列有分种检索表、种的文献引证、标本引证、生境与分布资料。  相似文献   

7.
Based on herbaria collections, three species of the fern genus Dryopsis ( Tectariaceae ) are recognized from Guangdong Province, China . They are D. heterolaena , D. mariformis and D. maximowicziana . Among the three species, D. mariformis and D. maximowicziana are new records to Guangdong . In the newly published book , Flora of Guangdong Volume VII , the name Ctenitis apiciflora (Wall . ex Mett .) Ching ( = D. apiciflora (Wall . ex Mett .) Holttum & Edwards) instead of D. heterolaena is recorded due tomisidentification . The morphological and ecological differences between D. heterolaena and D. apiciflora are discussed . A key to the three species, habitat and distribution data on the three species are given .  相似文献   

8.
Squamation and scale morphology provide interesting characters for phyletic analysis within the Cichlidae. It is not known, however, to what extent these characters are genetically fixed or determined by environmental parameters. To clarify this point, a study on Sarotherodon galilaeus was conducted. This species has an extensive distribution and lives in markedly different environments. Most scale characters were found to be remarkably stable within the species. The only large variations occur in scale counts, extent of caudal fin Squamation, number of circuli and radii, and the extent of scale granulation. The Squamation pattern, the form of the circuli and radii, the shape of interradial rostrad projecting tongues, the denticles on the circuli in the rostral field, and especially the kind of granulation in the caudal field is similar in all specimens examined and is also retained in fish bred in aquaria for several generations. Thus it seems justified to assume that these characters are strongly determined by genetic factors and that their analysis can be useful in the determination of phyletic relationships.  相似文献   

9.
Brycon species are present in various basins in Brazil and were or still are part of commercial fisheries and aquaculture activities ( Ferreira et al. 1996 , Mendonça 1994 ). Despite the importance of this group of fish, natural populations of some Brycon species are endangered ( Lins et al. 1997 ). Here, we describe the characterization of seven microsatellite loci that will be useful for the genetic studies in natural and captive populations for these and other species of Brycon.  相似文献   

10.
Typical thoracic setae are composed of longitudinally arranged cylinders ending as teeth at the oblique distal surface. Most thoracic 'blades' are rounded in cross section and show bilateral asymmetry. Some have teeth in oblique rows ("cross striations") on the side adjoining the tube wall. Sickle setae found posteriorly on the thorax have distal portions like abdominal setae. These are flat, each composed mainly of a palisade of spatulate units. On one side cylindrical elements may also be present, in patterns which are characteristic of some taxa. Uncini are made of rows (sometimes single) of shorter cylindrical elements with hooked ends pointing anteriorly. Anterior thoracic hooks are usually blunt, but pointed in the genus Janua. The collar setae assist withdrawal into the tube, the abdominal setae help with emergence, whilst other thoracic setae act as distance pieces, pushing the body to anchor the thoracic uncini against the opposite wall. The other uncini are brought into use by the prehensile abdomen. The flaccid ends of the sickle setae are readily lost in some taxa and their development or loss may reflect unimportant variations in strength of the adjacent abdominal field. Fin and blade setae are not very different from simple setae and the natural grouping of the genera into subfamilies shows that changes from one form of collar seta to another have occurred independently several times.  相似文献   

11.
In both examined species of Hirudinea there are paired spheroid ovisacs, and within each ovisac two convoluted ovary cords occur. The morphology of the cords is characteristic: their apical end is club-shaped, the central part is narrow and may contain developing oocytes, whereas the basal end of the cord is irregularly shaped and composed of degenerating cells. The ovary cords are built of somatic and germ-line cells; the latter are united into syncytial cysts. Each germ cell in such a cyst has only one stable cytoplasmic bridge connecting it to the central anuclear cytoplasmic mass, the cytophore. Initially all germ-line cells in a given cyst are morphologically identical, then the fates of cells diversify. Most of them become nurse cells and eventually degenerate; the rest continue meiosis, gather macromolecules, cell organelles and nutritive material and become oocytes. The oogenesis found in the species studied should be regarded as meroistic. Previtellogenic oocytes protrude from the cord into the ovisac lumen, whereas the vitellogenic ones float freely in the ovisac lumen. The somatic cells found in the ovary cords are: follicular cells which form the envelope of the cord and are also found among germ cells inside the cord, and one, huge apical cell that always is located at the top of the club-shaped end of the ovary cord. The apical cell has several characteristic features, e.g., it forms long cytoplasmic projections filled with intermediate filaments and it is connected to the neighbouring cells (both somatic and germ-line) via hemidesmosomes. We suggest that the apical cell forms the niche for maintaining germ and somatic stem cells. Generally, the organization of the ovary cords found in both studied species is broadly similar to those described in other hirudiniform leeches studied to date.  相似文献   

12.
13.
14.
GABA(B) (gamma-aminobutyric acid type B) receptors are important for keeping neuronal excitability under control. Cloned GABA(B) receptors do not show the expected pharmacological diversity of native receptors and it is unknown whether they contribute to pre- as well as postsynaptic functions. Here, we demonstrate that Balb/c mice lacking the GABA(B(1)) subunit are viable, exhibit spontaneous seizures, hyperalgesia, hyperlocomotor activity, and memory impairment. Upon GABA(B) agonist application, null mutant mice show neither the typical muscle relaxation, hypothermia, or delta EEG waves. These behavioral findings are paralleled by a loss of all biochemical and electrophysiological GABA(B) responses in null mutant mice. This demonstrates that GABA(B(1)) is an essential component of pre- and postsynaptic GABA(B) receptors and casts doubt on the existence of proposed receptor subtypes.  相似文献   

15.
The occurrence in the North Sea of a specimen of the white pomfret, Pampus argenteus (Euphrasen, 1788), a mesopelagic fish which is native to the Indian Ocean and particularly South-east Asia and the East China Sea, is described. Other anomalous distribution records for the same species are examined and some possible explanations investigated.  相似文献   

16.
Floral morphology, anatomy and histology were studied in representatives of all families of current Oxalidales, which were recently constituted as a result of molecular systematic studies by other authors, and are composed of families of different positions in traditional classifications (Oxalidaceae, Connaraceae, Brunelliaceae, Cephalotaceae, Cunoniaceae, Elaeocarpaceae, Tremandraceae). Two of the three pairs of sister (or nested) families that come out in molecular analyses are highly supported by floral structure: Oxalidaceae/Connaraceae and Elaeocarpaceae/Tremandraceae, whereas Cephalotaceae/Cunoniaceae are not especially similar at the level of Oxalidales. Oxalidaceae and Connaraceae share petals that are postgenitally united into a basal tube (although they are imbricate in both) but free at the insertion zone, stamens that are congenitally united at the base, uniseriate glandular hairs on the stamen filaments, and ovules that are hemianatropous to almost orthotropous. The sharing of a special type of sieve-tube plastids and of trimorphic heterostyly, studied by other authors, should also be mentioned. With Brunelliaceae, the two families share an androgynophore and nectaries at the base of the stamens in alternisepalous sectors. Elaeocarpaceae and Tremandraceae share buzz-pollinated flowers and a syndrome of features functionally connected with it. In addition, petals are larger than sepals in advanced bud, they are valvate, involute and enwrap part of the adjacent stamens, they have three vascular traces. Lignified hairs are common on the anthers and are found in the ovary locules and on the ovules (not lignified) of representatives of both families. Ovules have a chalazal appendage, and the inner integument is much thicker than the outer.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 321–381.  相似文献   

17.
Climbing perches use the tail for forward propulsion when on land. The spiny gill covers are used to obtain purchase on the substratum. Unusually amongst teleosts, the opercular and subopercular bone are not bound strongly together into a single operculum. Instead they are joined only by a thin, flexible membrane, so that the fish has two sections of the gill cover hinged separately; the opercular on the suspensorium and the subopercular on the rearmost part of the lower jaw. The gill covers open very widely and the subopercular rotates ventrally as well as laterally. Two modes of locomotion are employed. Usually Anabus adopts a near-upright posture and alternately drives the left and right spiny suboperculars into the substratum, using the tail to vault over the subopercular (which acts in the manner of a short vaulting pole). During vigorous movement the fish may leave the substratum altogether during the vault. Fatigued fish, or fish which have fallen during climbing, move on their sides, using the tail for propulsion and a single spiny opercular which is repeatedly driven into the substratum. Maximum speeds observed on land corresponded to 1.8 body lengths S?1. No evidence of involvement of the pelvic fins in locomotion was obtained; the pectorals seemed only to help in tilting the head from side to side and did not contribute significantly to forward propulsion. On mud and tree bark the fish were laterally unstable, often resting on their sides. Grassy substrata provided support and permitted a more upright posture. Slope climbing ability was restricted to 25° when climbing tree bark and 30° when climbing grass. Coupled with lateral instability these observations disqualify the species from any tree-climbing capacity. Anabas can climb vertical obstacles of at least half body length in height by pushing the head against the obstacle, using the spiny gill covers for purchase until one or other subopercular hooks over the top of the barrier. The subopercular is then used as a fulcrum for an upwards vault to clear the obstacle.  相似文献   

18.
19.
Perapion connexum (Schilsky) is recorded for the first time from Hungary and Kyrgyzstan, and new distribution data from Ukraine and Russia are provided. Preliminary placements of this weevil in faunal checklists for Poland and Slovakia are here documented with detailed data. Its occurrence in Austria based on older evidence, is discussed. The neophytic and invasive in Central Europe sorrel Rumex confertus Willd. is confirmed to be its unique host plant in Poland. Morphology of the newcoming weevil is described and illustrated, and the key to all Central European species of Perapion is presented.  相似文献   

20.
Thirty-five species of the family Lecanidae are examined from Tripura state in North-Eastern India. Of these, Lecane levistyla and L. scutata are interesting cold-water forms; L. batillifer is an Australasian element; L. acanthinula and L. sinuata are Oriental endemics and L. braumi, L. lateralis and L. simonneae are palaeotropical species. The lecanid fauna also includes the pantropical L. thienemanni and L. sola while the remainder are cosmopolitan and tropicopolitan elements. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

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