THE NAUTILUS. 125 



elevated ; aperture nearly circular, slightly flattened abovt and modi- 

 fied by the carinae ; lip simple, sharp, appressed to the lower half of 

 the body whorl ; umbilicus wide, exhibiting all the whorls. Height 

 3^, width 6^ mm. 



Valvata bicarinata Lea, P. A. P. S. II. 81, 83 (1841). Schuyl- 

 kill river, Pa. (Lea), Columbia, Pa., Philadelphia, Pa., and Port 

 Oram, N. J. (Walker), and Mercer Co., 111. (Marsh). 



The distinguishing characteristics of this species as compared 

 with V. tricarinata have already been stated. The localities above 

 mentioned are the only ones brought to my notice, but it will prob- 

 ably be found in the intermediate region. 



Var. normalis, n. v. (fig. 5). Body whorl tricarinate, otherwise 

 like the type. Muscatine, la. and Utica, 111. 



As in the case of Polyyyra andrewsce W. G. Binn., the typical 

 form of this species is really only a variety of the real specific type. 

 In a single specimen from Utica, 111., collected by J. H. Ferriss, a 

 fourth carina is developed on the upper surface of the last whorl at 

 about its first third, and revolves parallel with the suture to the 

 aperture, the space between forming a deep groove. 



III. Valvata utahensis Call. (fig. 7). 



Shell turbinate, thin, translucent, shining; yellowish horn color 

 at the apex, white or greenish white below' ; whorls 4, convex, 

 regularly increasing, minutely striate, the uppermost shouldered, 

 with a single, well marked carina which becomes obsolete on the 

 body whorl ; spire obtusely elevated, apex depressed ; suture well 

 impressed; aperture circular, slightly angled posteriorly; lip simple, 

 nearly continuous, appressed to the body whorl ; umbilicus small, 

 round, defined by a more or less obvious angle around the base of 

 the shell. Height 4^, width 4^ mm. Utah Lake and Bear Lake, 

 Utah. 



Valvata sincera \. utahensis Call, Bull. U. S. Geol. Sur., No. 11, 

 p. 44, PI. VI., f. 1-3 (1884). Valvata utahensis Call, Proc. Dav. 

 Acad. Nat. Sci. V, p. 4, PI. I, fig. 1-3 (1886). 



This species, which is more nearly related to V. tricarinata var. 

 unicarinata than to any other of the eastern forms of Valvata, is 

 well characterized by its more elevated spire, more globose form, the 

 obsolescence of the carina? on the body whorl and the much smaller 

 umbilicus. 



