358 INVERTEBRATA OF MASSACHUSETTS. 



and sometimes conspicuous revolving lines and grooves ; whorls 

 four or five, convex, well defined by the suture, forming a moder- 

 ately elevated spire, rather obtuse at its apex ; last whorl three 

 fourths the length of the shell ; aperture one half the same, ob- 

 liquely broad-ovate ; outer lip bevelled within to a sharp edge ; the 

 pillar margin is broadly flattened, and, widening forwards, projects 

 so as to form an angle ; within colored, generally brown, except the 

 bevelled edge, which is yellowish-white ; operculum homy, sub- 

 spiral ; sometimes a small umbilical indentation is found. Length 

 ^ inch, breadth f inch, divergence 68. 

 Found on rocks of the ocean shore. 



It is usually of a much smaller size than above mentioned. Indeed, 

 had it not been for a few large specimens sent me by Dr. L. M. Yale, 

 from Martha's Vineyard, which correspond, in every respect, with 

 specimens of L. rudis received from Mr. Sowerby, I should not have 

 recognised the species. The small specimens, such as we usually 

 find on the ocean rocks, ansv/er well to Mr. Say's description of Turbo 

 obligatus, and were doubtless the shells intended by him. They are 

 usually darker colored, and more mottled, than adult specimens. Mr. 

 Say thought his specimens might be mere varieties of his T. palliatus, 

 with obtuse, elevated, revolving lines. He must have inadvertently 

 associated them with that species, to which they have no affinity, in- 

 stead of with his T. vestitus, to which they are closely allied, and 

 from which they would not be distinguished by the unpractised eye. 

 The conviction that they are the L. rudis, has greatly diminished the 

 number of what I had regarded as varieties of L. tenebrosa. 



The variations consist in the greater or less prominence of the re- 

 volving lines ; sometimes these are almost imperceptible, and at others 

 they would bear the name of ribs. The coloring is principally yellow, 

 of various shades ; some small specimens are quite white ; many are 

 olive and grey. Dr. Loven has named a flesh-colored variety L. in- 

 carnata* 



From L. palliata, it is distinguished by its more elevated spire, and 

 distinctly defined whorls, its striated surface, and the compression of 

 the lip in front, so as to form an angle ; from L. tenebrosa, it differs in 

 its less elongated spire, its larger aperture, encircled as it were by a 

 broad, thick, flattened rim. 



I have not seen the animal, but Montagu says it is yellowish, with- 

 out stripes or spots ; the tentacula of the same color, marked with a 



