302 NEW MELANIDiE OF THE UNITED STATES. 



GONIOBASIS NIGRINA. PI. 37, fig. 137. 



Testa lsevi, parva, conica, subtenui, nigricanti, polita ; spira subelevata ; suturis irnpressis; anfraotibus, 

 regulariter convexis; apertura parva, ovata, superne angulata, intus tenebroso-purpurea ; columella 

 incurva, purpurea. 



Shell smooth, small, conical, rather thin, nearly black, polished ; spire somewhat 

 elevated ; sutures impressed ; whorls regularly convex ; aperture small, ovate, an- 

 gular above, dark purple within ; columella incurved, purple. 



Operculum dark brown, the polar point being low down and near to the left 

 margin. 



Proc. Acad. Nat. Sci. vol. 8, p. 80. 



Hob. — Clear Creek, Shasta County, California, Dr. Trask. 



My cabinet and cabinet of Dr. Trask. 

 Diam. "23, Length - 67 inch. 



Rernarlcs. — A number of good specimens with their opercula, were sent to me by 

 Dr. Trask. In form, size and color, this species is very like to Melania semicarinata, 

 Say, from Georgia and South Carolina. It may be distinguished at once by not 

 having the carination of that species which is usually strongly marked. It is not 

 quite so high in the spire, and the aperture is more rounded at the base. In all the 

 specimens of nigr'ma which I received, the apex is worn off. In the half grown ones 

 I can see no disposition to carination or plication in the upper whorls. I should sup- 

 pose that in perfect specimens, the number of whorls would be found to be about 

 seven, and that the aperture would be about the third of the length of the shell. In 

 some of the specimens there is a disposition to put on a few fine striae, and in most 

 of them there is a very small angular line running below the suture. I am not ac- 

 quainted with Dr. Gould's Melania silicula and bulbosa from Oregon, described in the 

 Proc. Boston Soc. Nat. Hist. July, 1847 ; but from the descriptions, I have no doubt 

 that they are different from both species herein described. 



Goniobasis Spillmanii. PI. 37, fig. 138. 



Testa lasvi, fusiformi, tenui, virido-cornea, fulgida, evittata; spira obtuse conoidea; suturis linearibus ; 

 anfractibus instar senis, planulatis, infra suturis sub irnpressis ; apertura magna, rliomboidea, intus 

 diaphana; labro acuto, parum sinuoso; columella parum inflecta, et tenui. 



Shell smooth, fusiform, thin, greenish horn-color, shining, without bands ; spire 

 obtusely conical ; sutures linear ; whorls about six, flattened, somewhat impressed 

 below the sutures ; aperture large, rhomboidal, diaphanous within ; outer lip acute, 

 slightly sinuous ; columella slightly bent in and thin, 

 Proc. Acad. Nat. Sci., 1862, p. 264. 

 Hab.~ Tennessee River, W. Spillman, M. D. 



