NATURAL SCIENCES OF PHILADELPHIA. 263 



importance of eliminating as many species as possible from Melania, which is 

 so enormously extended as almost to prevent the possibility of finding suitable 

 names for its species. In the Proceedings of tbe Academy, December, 1861, I 

 stated that Professor Haldeman's genus Lithasia formed a very excellent group. 

 In working up a very large number of the family Melanidce, obtained from the 

 Southern and Western States, I have, notwithstanding the divisions which had 

 been made, found myself embarrassed with that form of aperture, which is 

 quite different from the auger-mouthed {Trypanostoma) species and the Lithasia, 

 to which latter they are most nearly allied. I mean those which usually, 

 though not always, have a slight thickening of the upper part of the columella 

 and no callus below, and which are also without the notch of Lithasia, although 

 subangular at base. In this subangular character they differ from Melania pro- 

 per, which are round or loop-like at the base. For this group I propose the name 

 of Goniobasis * which will give us for our American Melanidce the following 

 genera, all of them having spiral opercida: 



Melania,] Lam. Anculosa, Say. lo, Lea. Lithasia, Hald. Sehizostoma, Lea. 

 Strephobasis, Lea. Trypanosoma, Lea. Goniobasis, Lea. Amnicola, Gould and 

 Hald. 



They may be known by 



Melania having a regular loop-form aperture. 



Anculosa having a rounded aperture and a callous columella. 



Io having a greater or less elongate channel or spout at the base. 



IAthasia having a callus on the columella above and below, and a notch at 

 the base. 



Sehizostoma having a cut in the upper part of the outer lip. 



Strephobasis having a retrorse callus at base and usually a squarish aperture. 



Trypanosoma having an expanded outer lip and an auger-shaped aperture. 



Goniobasis having usually a subrhomboidal aperture, subangular at base and 

 without a channel. 



Amnicola\ having a round mouth and no callus. 



Goniobasis oscclata. Testa laevi, pupaeformi, subelevata, subcrassu, luteo- 

 fusca, quadrivittata; spira subelevata; suturis valde et irregulariter impressis; 

 anfractibus septenis, convexiusculis ; apertura parva, constricta, subelliptica, 

 intus albida et vittata ; labro acuto ; columella alba, inflecta, ad basim contorta 

 et subangulata. 



Bab. Coosa River, Alabama, E. R. Showalter, M. D. 



Goniobasis Brumbyi. Testa, losvi, attenuate, subtenui, cinerea, quadrivit- 

 tata; spira attenuata, ad apicem carinata, ; suturis valde impressis; anfracti- 

 bus instar octonis, convexiusculis ; apertura parva, subrhomboidea, intus 

 albida et quadrivittata; labro acuto; columella inflecta, ad basim obtuse 

 angulata.. 



Ilab. Alabama, Prof. Brumby. 



Goniobasis Grosyenorii. TestS, Isevi, subattenuata, tenui, cornea, fulgida, 

 evittata; spira subattenuata, mucronata, ad apicem carinata; suturis regu- 

 lariter et valde impressis ; anfractibus octonis, convexis ; apertura parva, sub- 

 rotunda; intus albida; labro acuto, paulisper sinuoso ; columella inflecta, 

 tenui et contorta. 



Ilab. Fox River, Illinois, H. C. Grosvenor; and Quincy, Ohio, J. Clark. 



* Adams's Elimia takes in part of this genus. 



t Cuvier describes Melania as having long tentacula, the eyes being on the exterioi 

 side about the third of the length. The eyes of Melania Viiginica, Say, are at the base 

 of short tentacula. I very much doubt if we have a single species in the United States 

 which properly belongs to this genus, which Cuvier considered amarula as the type and 

 Lamarck asperata as the type. 



% Amnicola, although much like Paludina, is more nearly allied to the Melanidce. The 

 operculum is spiral, and thereiore very different in this character from Paludina. 



1862.] 



