306 LITTORINID^. 



it differs in its less elongated spire, its larger aperture, encircled as 

 it were by a broad, tliick, flattened rim. 



I have not seen tlie animal., but Montagu says it is yellowish, 

 without stripes or spots ; the tentacula of the same color, marked 

 with a dusky streak on the outside. If so, we should have another 

 decisive distinguishing mark. 



After long and careful observation and study of the myriads of 

 specimens on our shores, so infinitely varied in proportions, color- 

 ing, and sculpture, I have become satisfied in my own mind to what 

 species they sliould be referred. The limits of the species too, in 

 adult specimens, are decidedly marked both by the shells themselves 

 and by the animals. But, as to the young, to use the language of 

 Montagu, " the shades and gradations are so intimately blended, 

 that it is scarce possiijle to determine what marks a characteristic 

 line of division." The anule of the front 1 reoard as the most con- 

 slant character of the last species. 



It seems almost incredil)lo that Mr. Say should have drawn upon 

 the State of Maine for specimens of shells which are so extensively 

 distributed and so innumeral)le with us ; and still more incredible 

 that, from the few specimens which he probably received, he shoidd 

 have discriminated and described the three species so accurately, 

 though, if my conclusions are correct, some of them were previously 

 described. 



Littorina tenebrosa. 



Fig. 166. 



Shell ovate-conical ; spire elevated, whorls tumid, with numerous revolving 

 lines, dark green or dusky brown, with interrupted cream-colored lines ; aper- 

 ture circular; purplish-chocolate within. 



Ticrbo tembrosiis, Montagu, Test. Brit. 303, t. 20, fig, 4. — Wood, Ind. pi. 30, fig. 6. — 



Maton and Rackktt, Lin. Trans, viii. 160, pi. 4, fig. 12. — Dillnvyn, Catal. ii. 



818. — TuRTON, Condi. Diet. 197, figs. 3G, 37. — Brown, Couch, of Great Brit. &c. 



— Fleming, Brit. Aniin. 298. 

 Turbo rcstittis, Sav, Journ. Acad. Nat. So. ii. 241 ; cd. Binnev, 82. 

 Litlorlmi tenebrosa, Gould, Inv. l,st ed. 259, fig. 166. --De Kav, N. Y. Moll. 10.'), pi. 6, 



fif?. 106. 

 Littorina rudis, part, Stimpson, Shells of New England, 33 



Shell small, ovate-conical, rather thin, dark olive or dusky brown, 

 usually prettily checkered with buff-colored broken lines, generally 

 oljscured by a gray or rusty coating ; spire elevated and pointed, 

 of five or six rounded, tumid whorls, marked with obscure revolv- 

 ing lines ; suture well defined ; lower whorl two thirds the length 



