PALUDINA VIVIPARA. 19 



the great number of synonyms which he has 

 added to those of Lamarck; thinking perhaps 

 that this might be a distinct species. He had 

 access to the American Conchology, as he 

 admits several species from it, and cites a 

 figure from the same plate upon which P. 

 vivipara stands. 



Being the first Paludina known to naturalists; 

 the fact that it is viviparous attracted early 

 attention, and became the foundation of its 

 specific name. I believe every species of true 

 Paludina will be found to be viviparous (or ovo- 

 viviparous) and know of eight distinct species 

 which are. 



EXPLANATION OF PLATE 6. 



Fig. la represents the opercle belonging to 1 and 2, 

 (from the Wabash); fig. 6 is the natural size of a young 

 shell taken from the former, which had been dried with 

 the animal enclosed; fig. 5 is a thin light coloured half- 

 grown shell from Alabama; and figs. 3 and 4 a variety with 

 a lengthened spire, copied from Say's figure, the original 

 specimen being probably from Florida. The shells from 

 the Wabash have a smaller and more circular aperture 

 than those from the South; and the half-grown have a 

 greater resemblance to the adult in form and color. 



I have cited Linna3us as authority for the preceding 

 species, because he was the first to describe it under the 



