Oocyte degeneration and altered ovipository activity induced by Paraquat in the freshwater snail Physa fontinalis (Gastropoda: Pulmonata).
Molecular cloning and expression pattern of metallotfiionein gene from the lefthanded shell, Physa acuta.
Chronic toxicity of tributyltin on development and reproduction of the hermaphroditic snail Physa fontinalis: influence of population density.
A brown speckled snail found in rivers, lakes, and streams, the hermaphroditic snail Physa
acuta has everything it needs to reproduce - each snail is both male and female at the same time.
Studies on cercariae from Physa gyrina Say, with descriptions of two new species.
During the summer of 1938, Byrd examined over 100 specimens of the aquatic snail Physa gyrina, and noted that 28 individuals were releasing one or more of five different species of trematode cercariae.
He indirectly intimated this over 95 years ago from his observations on the sensitivity of the mantle of Physa gyrina Say, 1821 to external stimuli.
This ability to escape both indigenous and introduced predators has undoubtedly been a useful attribute in the colonization of many parts of Africa by Physa acuta Draparnaud, 1805 and Aplexa marmorata (Guilding, 1828) (= Physa marmorata Guilding, 1828) (Brown 1994).
Data on Physa experiments were even more indicative of depression in the presence of fish.
The Physa comparisons had three (of eight) with egg mass index values higher than the controls and another was equivalent.
The most common taxa found were the snail genus Physa, the midge Parachironornus abortivus, and the midge Chironomus decorus (Table 1).
The most common taxa found were bryozoans (Bryozoa), aquatic earthworms, the snail genus Physa, and Hydra (Table 1).