THE NAUTILUS. 79 
LIMN2&ID. 
Limnea viator VOrb. Montevideo: creek in the Prado. 
Planorbis heloicus d’Orb. Montevideo, back of Cerro. The 
typical and a large less shining form, diam. 10 mm. 
Planorbis peregrinus d’Orb. Montevideo, back of Cerro. 
Planorbis paropseides d’Orb. (?). Creek in Prado, Montevideo. 
Agrees well with d’Orbigny’s description and figures, but on ac- 
count of the locality may be a different species. 
Planorbis castaneonitens Pils. & Van., n. sp. Near Maldonado. 
ANCYLIDE. 
Ancylus obliquus Brod. & Sowb. San Gabriel’s Island, on stones 
in Rio de la Plata. 
The specimens vary considerable in degree of curvature of the 
apex, but are apparently all referable to this species, which was 
originally described from Chili. 
AMPULLARIID. 
Ampullaria neritoides d’Orb. La Plata River, San Gabriel’s 
Island, Uruguay; Uruguay River at Paysandu. Specimens with 
the interior pure white as well as the usual purple form. 
Ampullaria canaliculata Lam. Rio de la Plata at Buenos Ayres, 
Palenno and Ensenada; Parana near Rosario and at Paraiso. The 
specimens vary from true canaliculata to the varieties insu/arum and 
australis. 
Ampullaria sp. A small form, not determined, occurred in the 
creek in the Prado, Montevideo. 
Ampullaria Roissyi d’Orb. Parana River near Rosario, Santa 
Fé province, Argentina. 
Ampullaria Spizii d’Orb. Parana River near Dos Hermanos 
(“ Two brothers”) Island. 
AMNICOLID2. 
Littoridina australis d’Orb. Creek in the Prado, and in a small 
spring back of the Cerro, Montevideo. We follow the usual identi- 
fication in this case, although not at all sure of its correctness. The 
larger specimens measure as much as 83 mm.- alt. 
Littoridina charruana d’Orb. (?). San Gabriel’s Island. 
Littoridina Isabellei d’Orb. (?). San Gabriel’s Island, with the 
preceding. 
