u 



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



lateral tooth with a smaller number of denticles than the inner. 

 Formula of the denticles: 24.2' ^ " -'^'^ ' ■'^*^' Shell rather large, 



Fig. 145. 



Lingual dentition of Gillia altilis. — [Stimpson.] 



subglobular, thin, subperforatc, smooth ; spire small ; suture not 

 impressed. Aperture large, broad, ovate, oblique ; outer lip 

 thin, acute, not projecting anteriorly. Operculum thin, corneous, 

 regularly ovate. Rostrum rather broad. Tentacles tapering, 

 pointed. Yerge small, simple, lunate. Ova-capsules hemispheri- 

 cal, each containing a single egg, and deposited singly or in 

 groups or linear series. 



Station, fresh water. 



Distribution, the eastern parts of the United States of Xorth 

 America. (Slimpson.) 



Gillia altilis, Lea. — Sliell smooth, subgloboi?e, thick, pale liorn- 

 color ; spire short ; sutures small ; whirls four, obtusely angular above ; 

 aperture large, nearly round, white. 



Santee Canal, South Carolina : Prof. "Ravenel ; Susquehanna 

 River at Havre de Grace, Md. 



(Paluclina altilis, Prof. Ravenel's letter.) My cabinet and 

 cabinet of P. H. Nicklin. Diam. .27, length .32 inch. 



Last summer I found a number of this globose little species 

 on the banks of the Susquehanna, and then considered it new, 

 but on examination I found I had the same species, Prof. 

 Ravenel having sent it to me years ago under the name of Paluditia aliilia. 

 I am not aware that Prof. R. has ever described it, never having seen any 

 account of it. His specific name for it is retained, but I have placed it 

 among the Melaniae, it having a distinct spiral operculum. It belongs to 

 a natural group in the genus Melanin, which have very low spires and a 

 very large body whirl. There is a very slight impression on the superior 

 part of the whirls below the suture. The aperture is about two-thirds the 

 length of the shell. The epidermis in young specimens is a very pale 

 yellow, almost white. {Lea.) 



Fig. 146. 



