124 



LAND AND FRESH-AVATER SHELLS OE X. A. [PART IL 



Helix amjulata, Rackett, Liu. Tr. XIII, p. 42, pi. v, f. 1 (1822).— Wood, 



Cat. Suppl. pi. vii, f. 12 : Haxley's ed. p. 226. 

 Helix bicannahis, Eaton, Zool. Text-Book, 194 (1826). 

 Planorbis enfjonatus, Conkad, N. Fresli Sh. Suppl. p. 8, pi. ix, f. 8 (1834). 

 — LiSTEK, 139-44? 



The specie ranges from the British Possessions to Kansas and 

 Georgia. 



It must not be confounded with Planorbis hicarinaius of La- 

 niarcli, An. sans Vert. vol. 7, Aug. 1822. 



Fig. 204 is a fac-simile of that of Say, and Figs. 20G and 207 

 of those of Rackett and Conrad. Haldeman, who saw the origi- 

 nal specimen of the latter declares it to he a monstrosity of Plan, 

 hicarinatus. The original descriptions are also given below. 



Fig. 206. Uilix anrjnlata, Rackett (/. c). — Shell im- 



perforate, concave on both sides ; first whirl 

 angulated on both sides. 



Hah. Near Lake Huron. Diam. J inch. 

 Transversely striate, pale yellow ; three to 

 HelUx angulata. four contiguous whirls ; aperture large, rimmed. 



(^Rachett.) 



Planorbis engonatus, CoNRAn. — Shell yellowish, triangulated above, spire 

 not profoundly impressed, side of the body 

 whirl flattened, and both margins carinated ; 

 aperture longitudinally subovate, slightly cani- 

 panulate. 



This species was found at Albany, N. Y., by 

 Mr. Alva Mason. It differs from all other 

 species of the United States in the flattened 

 forn> of its lateral or outer margin. {Conrad.) 



Planorbis bicarinatus of Sowerby's Genera of Shells appears 

 rather to be identical with PI. canvpanulatus. 



Fig. 207. 



Planorbis engoruttus. 



