BULINUS. 



99 



I have seen no specimen of this species, but do not doubt its 

 belousj-ine: to Bulinus. 



169. 



Bulinus elatus, Gould. — Shell lanceolate-ovate, very thin, smooth 

 and glistening, pale born-color, colorless at suture ; spire acute ; whirls 

 nearly six, distinct, slightly convex, the last one seven-eighths the length 

 of the shell, ellipsoidal, nearly symmetrical at the ends ; aper- 

 ture three-fourths the length of the shell, narrow obovate- 

 lunate, acutely rounded anteriorly ; having on the pillar an 

 imperfect fold, and a very thin callus on the body whirl. 

 Length seven-eighths of an inch ; breadth three-eighths of an 

 inch ; length of aperture five-eighths of an inch. 

 Inhabits Lower California : Maj. Rich. 



An elongated species almost as slender as P. hypnorum, 

 though very much larger, highly polished, with a very long 

 aperture; pillar region -tumid. (^Gould.) 



Physa data, Godld, Bost. Journ. Nat. Hist. VI, 379, pi. xiv, f. 4 (1853) ; 



Otia, 185. 

 Aplexa elatn, Carpenter, Br. Mus. Cat. of Mazatlan Shells, p. 180 (1856). 



A copy of Gould's description and a figure of an authentic 

 specimen are given above. 



It is the thinnest and most delicate of the Xorth American 

 species. 



Cat. No. 

 9214 



No.ofSp. 



1 



From whom received. 



Judge Cooper. 



Fig. 170. 



Bulinus Iiypnoruni, Linn^us. — Shell heterostrophe, pale yellow- 

 ish, very fragile, diaphanous, oblong, whirls six or seven ; spire tapering, 

 acute at the tip ; suture slightly impressed ; aperture not 

 dilated, attenuated above, about half as long as the shell ; 

 columella much narrowed near the base, so that the view may 

 be partially extended from the base towards the apex. 



Inhabits shores of Illinois. Length 7-10 inch ; greatest 

 breadth 3-10 nearly. Animal deep black, immaculate above 

 and beneath ; tentacula setaceous ; a white annulation at 

 base. • 



In the fragility of the shell, this species approaches nearest 



to Limnsea columella. It is very common in stagnant ponds 



on the banks of the Mississippi. When the shell includes 



the animal, it appears of a deep black color, with an obsolete testaceous 



spot near the base on the anterior side. Its proportions are somewhat 



similar to those of P. hypnorum. (P. elongata, Say.') 



