414 HELICID^. 



Helix Cronhheitei* Newcomb, Proc. Cal. Ac. N. S. iii. 180 (1865). 



Patnla Cronlcheitci, Tryon, Am. Journ. Conch, ii. 263 (1866). 



Patula striatella, Morse, Journ. Portl. Soc. i. 21, fig. 48; pi. 2, fig. 6; pi. 8, fig. 49 



(1864). 

 Anguispira striatella, Trvox, Am. Journ. Conch, ii. 262, pi. 4, fig. 51 (1866). 



Shell small, orbicular, very much depressed, almost discoidal, of 

 a uniform reddish horn color ; whorls four, flattened above and 

 rounded below, separated by a well-defined suture, deli- 

 ^'^■^'*' cately wrinkled l)y the elevated and sharp lines of growth, 

 and in all immature stages presenting a sharpened or car- 

 inated edge at the circumference ; aperture rounded, de- 

 clining, somewhat broader than high ; lip simple and thin ; 

 lower surface rendered cup-shaped l)y a broad and deep um- 

 H. stria- jjilicus, wliosc diameter is nearlv that of the outer volution. 

 Diameter about one fourth of an inch. 

 The animal has the tcntacula bluish-black ; margin and posterior 

 part of foot white. Foot transparent, less than twice the diameter 

 of the shell in length ; terminating acutely. 



This is a northern species, Ijeing found through British America, 

 at Great Slave Lake, &c., Canada, and New England, and extends 

 to Virginia and Kansas. Also on the Pacific side of the Rocky 

 Mountains, near Hell Gate River. Found abundantly in all parts 

 of this State, about old stumps, and under the bark of decaying 

 logs. 



The cup-shaped base, and beautifully raised lines of growth, suf- 

 ficiently designate this shell. Its form is like that of H. rotundata 

 of Europe, which, however, is checkered by darker bars, like our H. 

 alternata. 



This is the shell, which, till recently, has been regarded as the 

 H. perspectiva of Say. Several gentlemen in Ohio, where both spe- 

 cies are found, have for some years discriminated the two shells ; 

 and in January, 1839, Mr. J. G. Anthony communicated to the Bos- 

 ton Society of Natural History a description of this species. After 

 mature examination, conchologists have become satisfied that the 

 Massachusetts shell is the H. striatella, and that H. perspectiva is 

 not found in this region. The differences are, that H. striatella is 

 altogether a more delicate shell in structure and marking, the num- 

 ber of whorls is one less, the color is lighter and the shell smaller ; 

 the sharp external edge is also more conspicuous, and, looking into 



* My opinion of this species is formed from the description alone. I have seen no 

 authentic example. — W. G. B. 



