Cercariae of the Lakes Maarsseveen (Netherlands) Infecting Bithynia spp. (Gastropoda: Prosobranchia) and Physa Fontinalis (Gastropoda: Pulmonata)
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منابع مشابه
The development of isolated blastomeres in Bithynia tentaculata (Prosobranchia, Gastropoda).
The development of isolated blastomeres, separated at the first and second cleavage has been studied. After separation at the first cleavage, one half-embryo (CD) becomes swollen and balloon-like and develops adult organs such as eyes, tentacles, shell, operculum, etc. The other half (AB) is much more compact and never develops these adult structures. After separation on the alternate axis at t...
متن کاملThe structure of a morphogenetic cytoplasm, present in the polar lobe of Bithynia tentaculata (Gastropoda, Prosobranchia).
In the first polar lobe of the egg of Bithynia tentaculata a cup-shaped mass of small vesicles is described, which fills the greater part of the lobe. It is named the 'vegetal body'. With methyl green-pyronin the vegetal body stains clearly, but after treatment with RNase no staining occurs, thus indicating the presence of RNA. The first polar lobe of Bithynia is of great importance for further...
متن کاملThe development of Bithynia tentaculata (Prosobranchia, Gastropoda) after removal of the polar lobe.
The polar lobe of the egg of Bithynia, with a volume of less than 1 % of that of the egg, was surgically removed. Lobeless embryos form no mesentoblast cell nor mesoderm bands. They fail to establish bilateral symmetry and to form eyes, foot, operculum, shell, etc. They always differentiate larval head cells, ganglia, larval liver and mesenchyme and sometimes columnar epithelium, stomodeal entr...
متن کاملThe Evolution of Kidney Function in the Neritacea (gastropoda, Prosobranchia)
Gastropod molluscs of the superfamily Neritacea (or order Neritacea: see Morton & Yonge, 1964) are found in marine, freshwater and terrestrial environments; but despite these wide differences in habitat the general anatomical organization is similar in all the members of the group. In particular the organization of the renal system appears to be very similar in marine and freshwater species, an...
متن کاملSpermiogenesis in the vermetid gastropod Dendropoma petraeum (Gastropoda, Prosobranchia).
The structure and maturation of the male gonad of the Mediterranean vermetid gastropod Dendropoma petraeum are described. Histological sections of the gonads were made throughout development and gonad activity was monitored at regular monthly intervals. During the autumn months the gonad is very small and is surrounded by a large quantity of connective tissue; it becomes more voluminous from De...
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ژورنال
عنوان ژورنال: Bijdragen tot de Dierkunde
سال: 1981
ISSN: 0067-8546,2666-0644
DOI: 10.1163/26660644-05101006