268 NEW MELANIDJE OF THE UNITED STATES. 



sent to me by Dr. Showalter, neither had an operculum. The soft parts of the animal 

 have not yet been observed. 



Genus GONIOBASIS. 



GONIOBASIS CRENATELLA. PL 35, fig. 79. 



Testa transverse striata, turrito-subulata, subcostata, parum plicata, subtenui, tenebroso-fusca, nigricante; 

 spira elevata, ad apicem crebro plicata; suturis vald6 impressis; anfractibus septenis, planulatis, 

 transversis eostis indutis ; apertura parva, elliptioa, intiis vittata ; columella albida, incurvata ; labro 

 subcontracto et valde crenulato. 



Shell transversely striate, high turrited, subcostate, somewhat folded, rather thin, 

 dark brown, almost black ; spire elevated, closely folded at the apex ; sutures very 

 much impressed; whorls seven, flattened, covered with transverse ribs; aperture 

 small, oval, banded within ; columella whitish, incurved ; outer lip somewhat con- 

 tracted and very crenulate. 



Melania crenatella, Proc. Acad. Nat. Sci., 1860, p. 93. 



Hah. — Coosa River, Uniontown, Alabama, E. R. Showalter, M. D. 



My cabinet and cabinet of Dr. Showalter. 

 Diam. "16, Length -50 inch. 



Remarlcs. — Five specimens of this very beautiful little species are before me, all of 

 which I owe to the kindness of Dr. Showalter. Most of these have eleven closely set, 

 thread-like, transverse ribs on the last whorl, which are very dark brown, while the 

 interspace is yellowish. On the next whorl above there are usually six, and above 

 these the number diminishes to three. There appear to be about seven whorls. 

 Within the aperture of four out of the five specimens there are brown bands ac- 

 companying the lines of the outer ribs, and these terminate in little furrows at the edge, 

 which cause the outer lip to be beautifully and regularly crenulate. One of the 

 specimens has the ribs without color, and therefore it is without bands inside. It is 

 allied to Melania ( Goniobasis) striatula, (nobis) , but is a much smaller species, more 

 cylindrical, of a darker color, and has stronger rib-like stria?. 



Genus TRYPANOSTOMA.* 



Testa conica. Apertura rhomboidea, inferno subcanaliculata. Labrum expansum. Columella lrevis, 

 inferno contorta. Operculum corneum, ad spiram pertinens. 



The enormous number of species in the genus Melania has made it very desirable 

 to eliminate as many as possible, by founding new genera, where well characterized 

 groups can be established. With this view I proposed in the Proceedings of the 

 Academy, in April last, the genus Strephobas-is. The genus now proposed under the 

 name of Trypanostoma will include all the well known Melania with an auger-shaped 



* Tgra-aw, aviger ; and ctto/xo., mouth. 



