106 



LAND AND FRESH-WATER SHELLS OF N. A. [PART III. 



Fig. 212. 



Neritina 

 showalteri. 



fossil in France. Some of tlie references quoted above are re- 

 ferred to Ferussac's species by Grateloup (Soc. Lin. Bord. XI, 

 127). I have not the means of settling the synonymy. 



^'eritella showalteri, Lea. — Shell smootli, rounded, semitrans- 

 parent, yellowish honi-color ; spire very much depressed ; sutures slightly 

 impressed ; whirls three, inflated ; aperture semi-rotund ; 

 inner lip dilated, white, thickened, without teeth and in- 

 curved ; outer lip acute, dilated and thin. Operculum — ? 

 Coosa River, ten miles above Fort William, Shelby County, 

 Alabama : E. R. Showalter, M. D. My cabinet, and cabinets 

 of Dr. Showalter and Dr. Lewis, and Academy of Natural 

 Sciences. Diam. .22, length .18 inch. 



The discovery of this shell by Dr. Showalter marks the 

 first notice, I believe, of the genus Neritina being found in our waters. 

 His very close observation and active investigations of the waters of 

 central and northern Alabama have enabled him to lay the naturalists of 

 this country under many obligations by new discoveries, and this is cer- 

 tainly one of much importance. We now see for the first time that this 

 genus, which is common in Europe, Africa, Asia, South America, and the 

 West Indies, also inhabits our southern rivers. I have great pleasure in 

 naming the species after the discoverer. This species is not allied to any 

 which has come under my notice. It is more rotund than usual, has a 

 clear horn-colored epidermis, smooth and shining. The substance of the 

 shell is so thin as to permit the column to be visible through it. The 

 inner lip is broad and slightly notched where it is in contact to the body 

 whirl. It is to be regretted that among the four specimens sent to me by 

 Dr. Showalter neither had an operculum. The soft parts have not yet 

 been observed. (Lea.) 



Neritina showalteri, Lea, Pr. Acad. Nat. Sc. Phila. l&Gl, 55 ; Journal 

 [n. s.], V, pt. 3, 267, pi. xxxv, f. 78, 78« (Mar. 1863) ; Obs. IX, 89. 



I can add nothing to the knowledge of this species contained 

 in Mr. Lea's description copied above. One of his figures is 

 copied in my Fig. 212. 



IVeritella jayaiia, Recluz. — Shell rather small, transversely-ovate, 

 thin, concentrically and delicately striated, yellowish under the epidermis, 

 varied with delicate angularly-flexuos6, reticulated, small 

 black lines and small white spots ; behind generally of an 

 uniform black ; whirls three, almost conic above, and with 

 a narrow canaliculated suture ; spire inclined towards the 

 side ; labium compressed, white with black spots, edentu- 

 late and scarcely arched in the centre ; labrum greenish- 

 yellow. Height 4.1, breadth 6, thickness 3 mill. 

 neritina Jayana. North America? 



Fig. 213. 



