LOCALLY INTRODUCED SPECIES. 457 



its columellar portion reflected. Axis of the truncated shell usually 

 about 25™'" ; diameter of the larjjest whorl less than 12""^ 



Helix (iecoUafa, Linn^us, S.vst. Nat., I"i47, »&c. 



BuUmus dccollatiis, Drapaknaud, 7fi, pi. iv, fig. 27, &c. — Pfeiffer, Mon. Hel. Viv., 



iv, 456.— BiNNEY, Terr. Moll., ii, 280, pi. i, fig. 1.— W. G. Binney, Terr. Moll., 



iv, 1:51.— Leidy, T. M. U. S., i, 259, pi. xv, figs. 5, 6 (1851), anat. 

 BuUmus miilHIatus, Say, Journ. Acad. Nat. Sci. PLllad., ii, 373 ; ed. Binney, 25 (err. 



typ. for mulilafus). 

 BuUmus viutUatufi, De Kay, N. Y. Moll., 56 (1843). — Pfeiffer, Men. Hel. Viv., ii, 153; 



iii, 397, — Reeve, Con. Icon., tig. 331. 

 Eumina deroUata, Tryox, Am. Journ. Conch., iii, 300 (1868). 

 Stenogyra decoUata, W. G. Binney, L. & Fr.-W. Sh., i, 228 (1869); Terr. Moll., v, 192. 



A European species, introduced at Charleston, S. C, where it has 

 increased very rapidly and has retained its position for more than 

 fifty years. It has also been introduced in Cuba and Brazil. 



Animal (see Fig. 471, p. 424) : Body short, extending but little behind 

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

 cidedly green reflections in certain lights, the sides and posterior ex- 

 tremity olivaceous ; surface finely granulated ; eye-peduncles slender 

 and rather short; ocular points very small 5 tentacles very short. The 

 shell is carried nearly horizontally when in motion. It is very vora- 

 cious 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 a box with them, one would 

 attack it, introduce itself into the inner whorls, and completely remove 

 the animal. Leaving a number ot Snccinea ovalis, Gld., with them one 

 day, the former 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 break- 

 ing off and abandoning successive portions of the spire. According to 

 the plan upon which the shell is projected, 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 whorls it releases its connection with the superior whorls, 

 creates a new attachment lower down, forms a new apex or spiral cal- 

 careous septum, which separates it from the abandoned part, and, in 

 some manner which is not understood, breaks and throws off those 



* I find no notice of any such carnivorous habits mentioned by Moquiu-Tandon. It 

 may be the species prefers vegetable food, but being deprived of that, was forced by 

 hunger to devour animal food. 



