178 INVERTEBRATA OF MASSACHUSETTS. 



Shell orbicular, depressed, slightly convex above and below ; 

 general tint a light fawn-color, which, on the upper surface, al- 

 ternates, in about equal proportions, with oblique, zigzag bars of 

 dark-brown ; these bars grow narrower and lighter on the lower 

 surface as they converge to the umbilicus ; they are generally in- 

 terrupted by a light-colored zone which issues from the middle of 

 the inner margin of the aperture ; whorls five to six, flattened 

 above, conspicuously plaited at the lines of growth so as to pro- 

 duce a rough surface above, but nearly smooth beneath ; the shell 

 has a sharp dividing line between the upper and lower surfaces in 

 all its earlier stages, which disappears only at maturity, forming a 

 circular aperture, slightly modified by the preceding whorl ; lip 

 simple and delicate ; umbilicus large and deep, exhibiting all the 

 volutions. Diameter often an inch. 



Animal with the head and tentacula of a light slate-color, back 

 brown, remainder of the upper surface brownish-orange ; eyes black ; 

 base of foot drab-colored ; collar saffron. Tentacula one third 

 of an inch long, blackish at tip. Foot not much exceeding the di- 

 ameter of the shell, terminating in a broad, flat, obtuse tip ; a light 

 marginal line runs along the foot from the head to the posterior tip. 



Found everywhere in old forests and in moist situations under 

 decaying logs and stumps. In this State it is not often found near 

 the sea-coast. Dr. Yale, however, has observed numerous dead 

 specimens on Martha's Vineyard. 



The shell varies in being more or less depressed, and the wrinkles 

 more or less obvious ; sometimes no bars are observable on the lower 

 surface. 



The animal and its tentacula are proportionally shorter than in our 

 other species. Its habits are gregarious, so that several are usually 

 found in company. 



Helix striatella. 



Shell small, orbicular, depressed, rufous ; whorls six, with prom- 

 inent lines of groicth ; aperture declining, rounded ; lip simple ; 

 base widely and deeply umbilicated. 



Figure 112. 



State Coll., No. 98. Soc. Cab., No. 2391. 



Helix striatella, Anthony ; Bost. Joiirn. JVat. Hist , iii. 278, pi. 3, f. 2, Binnky ; 

 Bost. Juvrn. JVat. Hist., iii. pi. 28, f. 3. 



