208 



TERRESTRIAL AIR-BREATHING MOLLUSKS. 



slightly curving ; tentacles prominent and conical, pellucid at tips. Respira- 

 tory foramen visible in the external angle of aperture. 



This is a well-defined species, always known by its subconical shape and tri- 

 angular aperture, nearly filled up by the coarse, projecting, columellar tooth. 

 The description here given applies to the most common form of the mature 

 shell, as ascertained from the examination of more than one hundred speci- 

 mens from different localities. Among a number of specimens there will of 

 course be different degrees of development and consequent variation from the 

 normal form. Specimens from particular localities seem always to be more 

 delicate, and never to attain that coarseness of parts in the aperture which is 

 common. There is sometimes a slight thickening of the left peristome near its 

 extremity. Mature specimens vary considerably in size. The aperture is 

 beautifully white within. 



Genitalia, jaw, and dentition unknown. 



Pupa rupicola, Say. ' 



Vol. III. PI. LXX. Fig. 1. 



Shell cylindrical, elongated; epidermis brownish horn-color ; whorls 6, con- 

 vex, the three anterior ones of nearly equal diameter, the three posterior dimin- 

 ishing very slightly, and forming an obtuse apex ; suture deep ; peristome 

 brownish, thickened within, widely reflected ; aperture lateral, semicircular, 

 truncated above by the body-whorl ; teeth 5, one on the middle of the colu- 

 mella prominent, compressed, emarginate in the middle, and often bicuspid ; 



Fig. 112. 



Pupa rupicola, enlarged. 



another at the termination of the axis, marking internally the situation of the 

 umbilicus, conical, and often composed of two or more tubercles ; a third in the 

 base of the aperture, a fourth upon the peristome, and a fifth, often massive 

 and prominent, deep in the fauces behind the columellar tooth;' umbilicus 

 minute. Length, 2 .V mill. ; diameter, 1 mill. 



Pupa rupicola, Say, Journ. Acad. Nat, Sci. Phila., II. 163 (1S21) ; Binney's ed., 

 22 (Cari/chium ?). —Gould, Bost. Journ. Nat. Hist., IV. 355, PI. XVI. Fig. 

 13 (1843). — Pfkiffek, Mon. Hel. Viv., II. 35S ; III. 557, nee Symboke, II. 

 55; in Chemnitz, ed. 2, p. 123, PI. XVI. Figs. 17 - 19. — DeKay, N. Y. 



