8TEN0GTRA. 229 



Bulimus mutilatus, DeKay, N. Y. Moll. 50 (1843).— Pfeiffer, Mon. Hel. 

 Yiv. II, 153; III, 397.— Reeve, Con. Icon. f. ;i31. 



An European si^ecies, introduced at Charleston, S. C, where 

 it has increased very rapidly, and has retained its position for 

 more than fifty years. 



Animal (see Fig. 389) : Body short, extending but little behind 

 the aperture, blackish, or bluish-black on the head and back, with 

 decidedly green reflections in certain lights, the sides and posterior 

 extremity olivaceous ; surface finely granulated ; eye-peduncles 

 slender and rather short; ocular points very small; tentacles 

 very short. The shell is carried nearly horizontally when in 

 motion. It is very voracious in its habits. I kept a number of 

 individuals received from Charleston a long time as scavengers, 

 to clean the shells of other snails. As soon as a living Helix 

 was placed in the box with them, one would attack it, introduce 

 itself into the inner whirls, and completely remove the animal. 

 Leaving a number of Succinea ovalis, Gld., with them one day, 

 they disappeared entirely in a short time. The Stenogyra had 

 eaten shell as well as animal.* 



The young shell is thin, transparent, and fragile ; the old is 

 opaque and rather thick. It is very peculiar in respect to the 

 manner of breaking off and abandoning successive portions of 

 the spire. According to the plan upon which the shell is pro- 

 jected, it would, when it reaches the full size which it attains in 

 this country, possess ten or more full volutions, if it retained all 

 of them from the apex downward. But as fast as the growth 

 of the animal compels it to increase the number and volume of 

 the whirls, it releases its connection with the superior whirls, 

 creates a new attachment lower down, forms a new apex or 

 spiral calcareous septum, which separates it from the abandoned 

 part; and, in some manner which is not understood, breaks and 

 throws off those whirls which are no longer of use.^ This com- 

 mences at a very early period ; the oi'iginal apex being thrown 

 off when the shell has acquired five or six whirls. They differ, 



' I find no notice of any such caraivorous habits mentioned by Moquin- 

 Tandon. It may be the species prefers vegetable food, but being deprived 

 of that was forced by hunger to devour animal food. 



2 Moquin-Tandon says (on the authority of Gassies) that the animal 

 breaks off the upper whirls by jerking round its shell against some hard 

 object. 



