Terrestrial gastropods are of global ecological and economic importance. This multi-author volume 14 chapters is a synthesis number aspects the biology these molluscs. The chapters, each written by well known authority (or authorities), vary in length, depth degree illustration. Each chapter has very useful reference section book good index.

Abstract The mature sperm of three species the subfamily Mytilinae ( Choromytilus meridionalis, Mytilus galloprovincialis, Aulacomya ater ) are primitive type. 50–55 μm long, with a distinct head, midpiece four to six mitochondria, and tail. In all acrosome is in form an elongated hollow cone; yet each has its own characteristic morphology, indicating that ultrastructure can be used as aid bivalve identification. A reexamination comparison acrosomes from five subclasses show subclass unique...

Book Title : The Ecology of Deep-Sea Hydrothermal Vents Author: C.L. van Dover. Princeton University Press, , New Jersey . 2000. Pp. 424. Price £24.95 (paperback). ISBN 0-691-05780-X.

A phylogenetic hypothesis for the patellid limpets is reconstructed by cladistic analysis of morphological characters from 37 species, representing all but one living members family. Characters included in are derived shell shape and microstructure, headfoot pallial complex, radula sperm. The species fall into four clades, providing basis a new classification monophyletic genera: Helcion (four species; southern Africa), Cymbula (eight Africa, eastern Atlantic, Indian Ocean), Scutellastra (17...

Light and transmission electron microscopy of the spermatozoa spermatogenesis 16 species (in three genera, Patella, Helcion, Cellana) patellid limpet have shown that head lengths sperm range from 3 to 13 μm, each has a with unique morphology, indicating can be used as taxonomic character. Although spermatozoon structure is specific, five types recognized, based on size, shape, nucleus acrosome. The occurrence morphological sperm, one which (Cellana capensis) particularly different other...

The Kariega estuary is an open which about 18 km in length. freshwater inflow into the very sporadic and consequently water often hypersaline at head. Quantitative qualitative sampling has been undertaken to describe distribution abundance of macrobenthos along estuary. Of 107 species that have recorded, 80% can be classified as euryhaline. One possible reasons for high diversity, when compared other eastern Cape estuaries, growth Zostera capensis entire length major contributors...

The mature sperm of Perna perna is 50-55 µm long and comprises three regions: a head, mid-piece tail. head incorporates round electron-dense nucleus an elongated cone-shaped acrosoma consists ring five mitochondria, in the centre which distal centriole from tail arises. early spermatid characterized by large perinuclear cytoplasm containing numerous mitochondria proacro- somal vesicles. By mid-spermiogenesis nuclear chromatin begins to condense, proacrosomal vesicles coalesce form acrosome...

Summary Dimorphic, and sometimes polymorphic, spermatozoa are a feature of many caenogastropod some archaeogastropod (s.l.) taxa. The two types sperm, named euspermatozoa (fertilizing) paraspermatozoa (non-fertilizing) by Healy Jamieson (1981), produced simultaneously in the same testicular acini. Paraspermatozoa develop from spermatogonia which similar structure to those producing euspermatozoa. Formation parasperm paraspermatocytes proceeds atypical meiotic divisions. Despite variability...

Transmission electron microscopy of the spermatozoa and spermatogenesis 11 species (in three suborders Chitonina, Acanthochitonina, Lepidopleurina) chiton has shown that each a sperm with unique morphology indicating can be used as taxonomic character. Although structure is species-specific, similarities between within subfamilies recognized. The from Chitonina Acanthochitonina have head comprising nuclear material only, anterior portion which in form long thin (approximately 80 nm diameter)...

The formation and structure of sperm bundles (spermiozeugmata), the vas deferens where are formed, in Pterostichus nigrita is described by light electron microscopy. spermiozeugmata sheet-like type consisting a central rod (about 3 mm long) electron-dense material (the spermatostyle), to which two spermatozoa 95 per bundle) attached. spermatostyle has spoon-shaped head, differentiated into an core more electron-lucent cortex. Spermatozoa 340 µm attached anterior portion only. Spermiozeugma...

Transmission electron microscopy of the spermatozoa five species from three families bivalves has shown that each a sperm with unique morphology. However, morphology acrosomes is typical subclass bivalve to which they belong. An examination spermatogenesis in species, along re-examination material six other bivalves, revealed pre-spermiogenic cells possess flagella. In addition, acrosome formation begins spermatocytes proacrosomal vesicles Golgi body. During spermiogenesis coalesce at...

Abstract Morphological and isozyme variations between 13 populations of the species hitherto named Patella granularis were investigated to see whether differences in shell structure west coast versus south east coasts southern Africa are supported by other morphological features or genetic differences. The shells showed a definite decrease size from east, but this is correlated with productivity no diagnostic use distinguishing populations. Discriminant functions analysis based on...

Journal Article COMPARATIVE SPERMATOLOGY OF THREE SPECIES DONAX (BIVALVIA) FROM SOUTH AFRICA Get access A.N. HODGSON, HODGSON *Department of Zoology & Entomology, Rhodes UniversityGrahamstown 6140, South Africa Search for other works by this author on: Oxford Academic Google Scholar R.T.F. BERNARD, BERNARD G. VAN DER HORST †Department Physiological Sciences, University the Western CapeSouth Molluscan Studies, Volume 56, Issue 2, May 1990, Pages 257–265,...