444 HELICID^, 



Maine, New Hampshire, and New York. 



I luivc not seen this species. Mr. Morse says it has hccn con- 

 founded with V. ouata, but is one fourth smaller, has one whorl 

 less, and a more circular columellar margin to the aperture, &c. 



Vertigo simplex. 



Fig. 121. 



Shell minute, cylindrical-ovate, smooth; whorls five; aperture circular, tooth- 

 less; umbilicated. 



Pupa simplex, Gould, Host. Journ. Xat. Hist. iii. 40-3, pi. 3, fig. 21 (1840) ; iv. 359 (1843) ; 



Iiiv. 190, fiy. 121 (1841). — Pfeiffeu, Mon. Hcl. Viv. ii. 302. — ])e Kay, N. Y. 



Moll. .52, pi. 36, fiij,-. 347 (1843). — Binney, Terr. Moll. ii. 343, pi. 72, fig. 3. 

 Vertiz/o siiupk.r, Stimpsox, Shells of New England, 53 (no descr. ). — W. G. Binney, 



'iVrr. Mull. iv. 148. — Morse, Am. Nat. i. 670, figs. 67, 68 (1868). 



Shell minute, two thirds of the shell cylindrical, surmounted 

 by a rapidly formed, blunt aj)cx, smooth, light chestnut colored. 



Whorls five, moderately convex, sei)arated 



TOO. •' , '■ 



by a distinct suture, quite smooth ; aper- 

 ture circular, except for a small section 

 from the posterior portion, which is cut 

 off by the encroachment of the preced- 

 ing whorl ; lip simjjle and sharp, slightly 

 everted on the left side, and partially 

 hiding a small uuibilicus. No trace of 

 a tooth has been detected in any of the si)ccimcns examined. 

 Length, one fifteenth of an inch ; breadth, one thirtieth of an inch. 

 The locality where this was first found is a small grove, a little 

 northward of Fresh Pond in Cambridge. In this place it has been 

 found among the moist leaves, on three successive visits in the 

 months of ^lay and June, in company with HelU lineala, labijrin- 

 thica, chersina, and indentata, and Pupa modesla. None of the 

 shells exhibit any trace of a tooth, althougb their aspect, and the 

 season of the year, indicate that they can be none other than adult 

 shells. Indeed, were it not for the infringement of the last whorl 

 but one on the aperture, we might rather refer the shell to Cydos- 

 toma than to Pupa. It occurs in Canada and New England. 



It is rather smaller than P. nwdcsta, and about the size of P. 

 pcrdodon; but the simi)licity of the unarmed, circular aperture dis- 

 tinguishes it from every American species. The aperture of P. mo- 

 desta, before the deveiopment of the teeth, is broader than long. 

 It is the analogue of the Vertig-o cdentula of Europe. 



