61 



Grenus Paludina. — Shell subovate, operculated ; aperture en- 

 tire, longitudinally ovate, narrowed above ; lip simple, not dilated 

 or reflected. 



Ohs. This genus has been very lately separated by Mr. La- 

 marck from the Q/cIostomx, with which it corresponds, except in 

 having no diluted lip, and the aperture is angulated above. The 

 animal has a short rostrum, two acute tentacula with eyes at their 

 external base, a small membranaceous wing each side of the body 

 before, foot double before, the wing of the right side is folded int^> 

 a small canal, by which the water is introduced into the respiratory 

 canal. Latr. To this genus will be referred several of the 

 Lymnse,a of the American Edition of Nicholson's Encyclopaedia 

 as L. decisUf vivipara and subcarinata. 



Paludina limosa. — Shell conic, subumbilicate, dark horn 

 colored, generally incrusted with a blackish irregular covering on 

 the spire, and sometimes on the body, which completely obscures 

 the obsoletely wrinkled epidermis ; aperture ovate-orbicular ; suture 

 impressed. 



Length three-twentieths, breadth one-teuth, of an inch. Cabi- 

 net of the Academy. 



Animal whitish ; head brown ; mouth, tentacula, orbits, and vitta 

 on each side of the neck, white ; tentacula filiform, more than half 

 as long as the base of the animal ; rostrum about half as long as 

 the tentacula, annulate with darker lines above ; foot white, 

 brownish above, short, suboval, truncated before, and rounded 

 behind. 



Extremely numerous on the muddy shores of the rivers Dela- 

 ware and Schuylkill, between high and low water marks. 



[J. A. N. S. vol. i. p. 280, June, 1818.] 



Planorbis glabratus. — Shell sinistral; whorls about five, 

 glabrous or obsoletely rugose, polished, destitute of any appearance 

 of carina ; spire perfectly regular, a little concave ; umbilicus large, 

 regularly and deeply concave, exhibiting all the volutions to the 

 summit ; aperture declining, remarkably oblique with respect to 

 the transverse diameter. 



Breadth nearly nine-tenths of an inch. Inhabits South Caro- 

 li na. Cabinet of the Academy. 



