DENTALIUM. 11 



surface, and, in some places, make with the longitudinal strise a fine 

 reticulated structure. Anterior aperture nearly round, but slightly 

 angulated in line with the principal ribs ; edges thin, but the shell 

 is thickened and the interior is circular farther back. The posterior 

 end is rather small, with a very small aperture, the shell being 

 thickened, but the tip is so eroded as to render uncertain the exist- 

 ence of a slight notch. Color dull grayish-white. Length 45, di- 

 ameter of large end 6, of small end 3 mill. ( Verrill). 



D. laqueatum VERRILL, Trans. Conn. Acad., vi, p. 431, pi. 44, f y 

 18 (1885J. DALL, Blake Kep., Bull. M. C. Z., xviii, p. 426, pi. 27, 

 f. 1 ; Bull. U. S. Nat. Mus., No. 37, p. 76, pi. 27, f. 1 (1889). 



Off Martha's Vineyard and Chesapeake Bay in 68 fms. (U. S. Fish 

 Commission) ; from near Cape Hatteras, North Carolina, to the vi- 

 cinity of Cape Florida, abundant (Blake Expedition) ; at Station 9, 

 Gulf of Mexico, in 127 fms.; off Sombrero, living, in 54 fms.; off 

 Havana, in 127 to 177 fms. (Sigsbee) ; off Santa Cruz, in 115 fms. ; 

 off Dominica, in 118 fms., sand; near the Grenadines, in 164 fms., 

 coral ; off Grenada, in 154 fms., ooze ; near Barbados, in 73-84 fms. 

 (Blake Exped.). 



This species is easily distinguished from all others of our coast by 

 the very large and strong longitudinal ribs, and the fine longitudi- 

 nal strise between them ( Verrill). 



This very fine species reaches the length of 55 mill. The very 

 young have generally a very slight wave on the convex side of the 

 anal aperture ; in the adults this aperture is somewhat circular and 

 unslit; sometimes there is a narrow slit 5 mill. long. The very 

 young have the transverse sculpture most prominent (aside from 

 the strong ribs which range from 9 to 11), the adolescent part the 

 longitudinal strife ; while near the lip of the adult both are obsolete. 

 I am disposed to think the species does not reach more than 200 

 fms. (DalL). 



It recalls D. octangulatum Don. somewhat, but the secondary 

 strise in that species, when present, are generally more numerous, 

 the primary ribs fewer, and the taper at the posterior end much 

 more abrupt. 



D. LINEOLATUM Cooke. Unfigured. 



Shell solid, pale amber colored, acuminate, curved toward the 

 apex, fluted with 9 angulated, very high, equidistant ribs ; inter- 

 stices and some of the ribs themselves longitudinally lineated, and 



