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1.
Morphological details of the testis, seminal vesicles and vas deferens of Orchestia platensis are described. The follicular lumen of the mature testis contains spermatogonia, spermatocytes, spermatids and spermatozoa. The histochemical nature of the testis and the vas deferens is elucidated. The spermatozoa and vas deferens contain acid sulphated mucopolysaccharides and neutral mucopolysaccharides. In addition, they contain basic proteins, disulphide groups, lipids, phospholipids, RNA and DNA.  相似文献   

2.
Volbehr  Ute  Rachor  Eike 《Hydrobiologia》1997,358(1-3):71-76
The work of Kazutsugu Hirayama over the past 25 yearspromoted the wide use of the marine rotifer Brachionusplicatilis as an experimental model in zooplanktonecology. His reports about the nature of geneticvariation in the B. plicatilis complex stimulated usto investigate how mate recognition maintains speciesboundaries. For the past several years, we haveexamined chemical communication between female andmale B. plicatilis. Here we report on the comparativebinding of polyclonal antibody against the materecognition pheromone (MRP) to three B. plicatilisstrains and three B. rotundiformis strains.Quantification of anti-MRP binding permitsinvestigation of how the female mating signal differsamong closely related Brachionus species and strains.Antibody binding reflects differentiation independentof the male receptor which has been describedelsewhere. Anti-MRP bound to females of all sixstrains and was localized in the corona. Antibodybinding greatly reduced mating in all three B. plicatilis strains. However, antibody bindingsignificantly reduced mating in only one of the B. rotundiformis strains. The MRP of both species has asimilar molecular weight, but the differential bindingsuggests that the mate recognition pheromone onfemales has differentiated in B. plicatilis and B. rotundiformis.  相似文献   

3.
The Lamina ganglionaris (first optic neuropile) of the decapod crustacean Pandalus borealis has its optic cartridges (synaptic compartments) arranged in horizontal rows. Each optic cartridge contains seven receptor axon terminals and the branching axis fibres of five monopolar second order neurons. Four types of monopolar neurons are classified. Their cell bodies are arranged in two layers. The inner layer contains the cell bodies of exclusively one of these types, and each cartridge is invaded by two neurons of this neuron type (type M 1:a and M 1:b). The outer layer contains the cell bodies of the remaining three types (M 2, M3 and M4). One gives rise to a large radially branched axis fibre in the centre of the cartridge. The other two have wide branches which may make inter-cartridge contacts, one proximally and the other distally in the plexiform layer, which is clearly bistratified. The receptor axons terminate in two levels corresponding to these strata. Two sets of tangenital fibres form networks in the proximal and the mid-portion of the lamina. Both networks have fibres with primary branches in the vertical plane and secondary branches in the horizontal plane. The fibres of the networks are derived from axons that pass from the second optic neuropile, the medulla externa.  相似文献   

4.
Moran  J. D. W.  Piasecki  W. 《Hydrobiologia》1994,292(1):171-178
Sphyrion lumpi is a sexually dimorphic, parasitic copepod which causes significant losses in fisheries in the North Atlantic. Studies involving both light and scanning electron microscopy revealed important details of the external morphology of both sexes that are discussed in relation to other members of the family Sphyriidae. Conclusions are drawn regarding the life cycle of S. lumpi. The present finding of this parasite on Urophycis tenuis constitutes a new host record.  相似文献   

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Oxygen consumption rates (QO2) of laboratory reared stage one zoeae of Pandalus borealis (Krøyer) at 1.5, 3, 4.5, 6, and 9°C were 1.5, 2.2, 2.6, 3.6 and 4.1μ O2 · mg?1 · h?1, respectively. These values of QO2 correspond to 0.26, 0.38, 0.44, 0.60, and 0.70 μl O2 · individual?1 · h?1. At 10.5 °C oxygen consumption rates decreased suggesting thermally induced respiratory stress.The equation log10QO2 = 0.55 log10T°C + 0.086 describes the relationship between QO2 (μl O2 · mg?1 · h?1) and sea-water temperature between 1.5 and 9°C. Corresponding values of QO2 for an individual (μl O2 · h?1) exhibited the relationship log10QO2 = 0.55 log10T°C ?0.686.The minimum daily metabolic caloric requirements for an individual zoea ranged from 0.04 at 3 °C to 0.07 calories per day at 8 °C. The number of calories ingested daily ranged from 0.4 to 0.5 at 3 to 8 °C.  相似文献   

8.
Wielkopolska (western Poland) is a region, with good reason, called the main food base of Poland. All indices of agricultural production have always been there (since 19th century) much higher than elsewhere in the country (Ratajczak 1977/1978, Buszko 1984, Gorzelak 1989, Czyzewski et al. 1992; table 1). Such a situation had a beneficial effect on the amount of the income generated by a family of Wielkopolska and, thus, decided on its better financial status. Additionally, rural inhabitants of this region have always been characterised by a more advantageous educational structure in comparison with people of other Polish villages. Generally, it is easy to detect the relationship between the life standard, the level of education and family planning. The aim of this paper is to assess fertility of women from villages of Wielkopolska in the period of transformation of the political and economic system in Poland.  相似文献   

9.
Summary Thysanote alternans n. sp., a lernaeopodid copepod parasitic on Polynemus sextarius is described and illustrated. A key to 19 species of Thysanote is provided (two unnamed species included). Specific diagnosis within the genus is based on the number and shape of maxillary and posterior trunk processes. The limitations of their value as discriminant characteristics are discussed. Host affiliations of the members of the genus are examined. Distribution of Thysanote is shown to have two centres, one in the Indian Ocean and another, a smaller one, in the Caribbean. The connections between them are tenuous. ac]19810127  相似文献   

10.
The behavior of the basic nutrients (NO3, PO4, SiO2) was studied in the estuary of the Razdolnaya River in low and high water, the flow was 4.3 × 106 m3/day and 10.8 × 106 m3/day, respectively. It was shown that within the limits of the euphotic zone the nutrients were characterized by a pronounced nonconservative behavior caused by their removal by phytoplankton in primary production. It was determined that phytoplankton removal of nutrients occurred with ratios C : NO3 : P : Si = 105 : 18 : 1 : 37 and C : NO3 : P : Si = 93 : 11 : 1 : 29 at a respective ratio P : NO3 : Si = 1 : 22 : 140 in low water and P : NO3 : Si = 1 : 17 : 120 in high water. It was also determined that the maximum rate of nutrient removal was 4 times higher in the high water than in the low water. The maximum value of primary production of phytoplankton was 2.5–4.0 gC/m2 day. The estuary area of the Razdolnaya River was specified by rather high production. Such a rate of estuarine primary production, caused by nutrients carried out by the river, being no less than 250 t of dry weight of phytoplankton a day, can provide daily production up to 800 t of biomass in the secondary chain of the ecosystem.Original Russian Text Copyright © 2005 by Biologiya Morya, Zvalinsky, Nedashkovsky, Sagalayev, Tishchenko, Shvetsova.  相似文献   

11.
Araujo  H. M. P.  Boxshall  G. A. 《Hydrobiologia》2001,444(1-3):197-202
The pre-metamorphic female of Therodamas serrani Krøyer, 1863 is described for the first time based on new material collected from the upper reaches of Piauí River estuary, northeastern Brazil. Females are present in the plankton throughout the year, and are common during the rainy season. Five of the six currently accepted species of Therodamas are known only from metamorphic females, making identification of pre-metamorphic stages problematic. Identification of T. serrani was made on the basis of the leg setation and the very similar proportions of the two apical endopodal spines on leg 1.  相似文献   

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The family Diplodactylidae is the most ecologically diverse and geographically widespread radiation of geckos within Australasia. Herein we present a first comprehensive phylogenetic analysis of relationships of diplodactylid geckos currently assigned to the genus Oedura, a group of relatively generalised arboreal Australian geckos. Maximum Likelihood, bayesian and Maximum Parsimony analyses of a combination of over two and a half kilobases of nuclear (PDC, Rag-1) and mitochondrial (ND2, ND4, tRNA) sequence data all identified four distinctive lineages within Oedura s.l. Based on their deep divergences and a suite of diagnostic morphological characters we recognise each of these four lineages as genera, two of which are monotypic and newly described herein. Our molecular data also suggest that Oedura s.l. is not monophyletic, but is instead a plesiomorphic grade restricted to islands of rocky or forested habitat around coastal and central Australia. In contrast, combined analysis of all data suggests the Australian arid zone is dominated by a single comparatively derived and relatively species rich clade including most other genera of Australian Diplodactylidae. Additional data are required to properly resolve basal divergence events within the Diplodactylidae, however the emerging pattern of relationships and divergence is consistent with the hypothesis that monsoonal and temperate lineages are ancestral to the arid zone fauna, but also indicate that arid zone lineages and radiations are relatively old, and potentially date back to the mid Miocene or earlier.  相似文献   

14.

Kabata separated species of Pseudocharopinus Kabata, 1964 and Charopinus Krøyer, 1863 in 1964 based mainly on four characteristics. Currently Pseudocharopinus has 11 species while Charopinus consists of three species considered valid. Pseudocharopinus malleus (Rudolphi in Nordmann, 1832) and Charopinus dubius T. Scott, 1900 were collected and studied from hosts off South Africa. Additional to previous reports from South African waters, P. malleus is reported from Torpedo sinuspersici Olfers and T. fuscomaculata Peters while C. dubius is reported from Leucoraja wallacei (Hulley) and Rajella dissimilis (Hulley), all new host records. In an attempt to estimate the evolutionary relationships among Pseudocharopinus spp. a cladistic analysis was performed by means of parsimony using described and illustrated features of the adult females. Due to the mostly unresolved 50% majority rule tree, a key for the identification of the adult females of Pseudocharopinus spp. is compiled. Additionally, a key for the identification of adult females of Charopinus spp. is provided.

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16.
The “tree of life” iconography, representing the history of life, dates from at least the latter half of the 18th century, but evolution as the mechanism providing this bifurcating history of life did not appear until the early 19th century. There was also a shift from the straight line, scala naturae view of change in nature to a more bifurcating or tree-like view. Throughout the 19th century authors presented tree-like diagrams, some regarding the Deity as the mechanism of change while others argued for evolution. Straight-line or anagenetic evolution and bifurcating or cladogenetic evolution are known in biology today, but are often misrepresented in popular culture, especially with anagenesis being confounded with scala naturae. Although well known in the mid 19th century, the geologist Edward Hitchcock has been forgotten as an early, if not the first author to publish a paleontologically based “tree of life” beginning in 1840 in the first edition of his popular general geology text Elementary Geology. At least 31 editions were published and those between 1840 and 1859 had this “paleontological chart” showing two trees, one for fossil and living plants and another for animals set within a context of geological time. Although the chart did not vary in later editions, the text explaining the chart did change to reflect newer ideas in paleontology and geology. Whereas Lamarck, Chambers, Bronn, Darwin, and Haeckel saw some form of transmutation as the mechanism that created their “trees of life,” Hitchcock, like his contemporaries Agassiz and Miller, who also produced “trees of life,” saw a deity as the agent of change. Through each edition of his book Hitchcock denounced the newer transmutationist hypotheses of Lamarck, then Chambers, and finally Darwin in an 1860 edition that no longer presented his tree-like “paleontological chart.”  相似文献   

17.
The paratypes of Trebius akajeii Shiino, 1954, originally collected from Dasyatis akajei (Müller & Henle) at Owase, Japan, and the paratypes and newly collected specimens of T. latifurcatus Wilson, 1921, previously collected from Urolophus and Myliobatis at Venice, California, are redescribed. New host records for T. latifurcatus are: Torpedo californica Ayres, Squatina californica Ayres, Rhinobatos productus (Ayres), Platyrhinoides triseriata (Jordan & Gilbert), Raja inornata (Jordan & Gilbert) and Gymnura marmorata (Cooper). A new species, Trebius heterodonti, is described from the horn shark Heterodontus francisci (Girard) collected from southern California waters. These three species of Trebius are apparently closely related to each other. Diagnostic characters of the species are provided along with a discussion on the taxonomic value of selected features.  相似文献   

18.
The development of comparative biology (systematics) has been of interest to philosophers and historians. Particular attention has been placed on the 'war' of the 1970s and 1980s, the apparent dispute among those who preferred this or that methodology. In this contribution we examine the history of comparative biology from the perspective of fundamentals rather than methodologies. Our examination is framed within the artificial-natural classification dichotomy, a viewpoint currently lost from view but worth resurrecting.  相似文献   

19.
The effect of food concentration on gut clearance time of a pelagic copepod, Pseudocalanus minutus Krøyer, was investigated. Gut clearance time was estimated from ingestion rate and gut content pigment of copepods which were continuously fed during experiments. The time estimated by this method was longer than that estimated by evacuation of gut content pigment in filtered sea water by a factor of 1.3 to 2.6. Gut clearance time showed fluctuation with food concentration over 1.6 to 3.3. h, whereas food category had little effect on the time.  相似文献   

20.
The present study re-examines the detailed morphology of the type-species, Diclidophora merlangi (Kuhn, in Nordmann, 1832) Krøyer, 1838, and other Diclidophora species parasitic on gadid fishes: D. denticulata (Olsson, 1876) Price, 1943, D. esmarkii (Th. Scott, 1901) Sproston, 1946, D. luscae (van Beneden & Hesse, 1863) Price, 1943, D. minor (Olsson, 1868) Sproston, 1946, D. palmata (Leuckart, 1830) Diesing, 1850, D. phycidis (Parona & Perugia, 1889) Sproston, 1946, D. pollachii (van Beneden & Hesse, 1863) Price, 1943 and the recently described D. micromesisti Suriano & Martorelli, 1984. An amended generic diagnosis of Diclidophora Krøyer, 1838 (synonym Diclidophora Diesing, 1850) is provided, which includes the presence of a prostatic vesicle in the terminal male genitalia and the distal fusion of the median and peripheral sclerites, a1 and c1 in the clamp anterior jaw. Macrouridophora n. g. is herein proposed for species previously considered in Diclidophora, which are parasitic on macrourid and morid fishes. The clamp morphology in Macrouridophora n. g. has distinct lamellate extension attachments to peripheral sclerites c1 and the distal portion of d1, with no distal fusion between a1 and c1 in the anterior jaw. Macrouridophora macruri (Brinkmann, 1942) n. comb. is chosen as the type-species. Nine other species are herein transferred to Macrouridophora n. g.: M. coelorhynchi (Robinson, 1961) n. comb., M. lotella (Machida, 1972) n. comb., M. nezumiae (Munroe, Campbell & Zwerner, 1981) n. comb. and M. tubiformis (Rohde & Williams, 1987) n. comb. are redescribed, based on the re-examination of type or voucher specimens. Macrouridophora attenuata (Mamaev & Zubtschenko, 1979) n. comb., M. caudata (Mamaev & Zubtschenko, 1984) n. comb., M. papilio (Mamaev & Avdeev, 1981) n. comb., M. paracoelorhynchi (Mamaev & Paruchin, 1979) n. comb. and M. physiculi (Mamaev & Avdeev, 1981) n. comb. have adequately described haptoral clamps in the literature. The clamp morphology in Macrouridophora sp. from Lepidorhynchus denticulatus in Australia is also considered. Diclidophora whitsonii Suriano & Martorelli, 1984 is herein transferred to the genus Macruricotyle Mamaev & Ljadov, 1975, as M. whitsonii (Suriano & Martorelli, 1984) n. comb. D. embiotocae Hanson, 1979 is herein considered a species incertae sedis. D. caudospina Khan & Karyakarte, 1983 and D. paddiforma Deo & Karyakarte, 1979 are herein considered species inquirendae. D. aglandulosa Deo, 1977, D. glandulosa Das, 1972, D. minuta Das, 1972 and D. spindale Deo, 1977 are formally dismissed as nomina nuda. The systematic position of Diclidophora Krøyer, 1838 and Macrouridophora n. g. in the subfamily Diclidophorinae Cerfontaine, 1895 (sensu Mamaev, 1976) is discussed.  相似文献   

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