390 cancellaeiidj:. 



Oemis TRICHOTROPIS, Brod. and Sowerby. 1826. 



Shell thin, ventricose, keeled, umbilicated ; aperture longer than 

 the spire, compressed into a partial canal in front; epidermis horny, 

 rising into hairs at the angles of the shell ; operculum horny, 

 nucleus at one side. 



The genus Trichotropis was instituted by Mr. Sowerby to include 

 this and one other shell, which have unequivocal generic traits, but 

 whose place in the series has not yet been determined. Lesson re- 

 gards it as allied to Jariihiiia; and the species which he knew might 

 well lead him to such an opinion. Mr, Sower! )y at first compared 

 it with Turbo, Buccimim, and Cancellaria. But in his late work, 

 the " Conchological Manual," he places it among the Purpuriferce, 

 where its aspect would lead us to place it. It is very peculiar in 

 having its axis fall considerably to the left of the canal. 



Tricliotropis borealis. 



Fig. 207. 



Shell ovate-rhomboidal ; whorls four, the last very broad, and encircled by four 

 or five, and the others by two prominent^ fringed ribs, and crossed by minute and 

 regular elevated lines ; umbilicated. 



Trichotropis borealis, Sowerby, Zool. Jouni. iv. 373, pi. 9, figs. 6, 7. — Gould, Inv. 1st cd. 

 300, fig. 207. -De Kay, N. Y. Moll. 137, pi 8, fig. 178. — Stimpson, Check Lists, 6. 

 Trichotropis costellalus, Couthouy, Bost. Journ. Nat. Hist. ii. 108, pi. 3, fig. 2. 



Shell ovate-rhomboidal, turreted, spire pointed ; color ashy or 

 yellowish-white ; whorls four, separated by a deeply channelled sut- 

 ure ; the last whorl very large, and encircled by two prom- 

 Fig. 651. jj^ent, and two or three less conspicuous, rounded ribs or 

 keels, and several still smaller intervening and adjacent 

 ones ; the two large ribs only are continued upon the up- 

 per whorls, which are thereby rendered angular ; very nu- 

 merous, minute, and regular threads traverse the Icngtli 

 of the shell, not being interrupted by the ribs ; the whole 

 is covered by a yellowish horn colored epidermis, which rises like a 

 bristly fringe along the keels, and along those lines which mark the 

 stages of growth ; aperture ovate, broad and rounded behind, nar- 

 rowed and somewhat pointed in front ; outer liji thin and sliarj), 

 festooned by the projecting ribs ; inner lip arched and flattened, 

 with a slight inward projection at the lower third, rising before the 



