72 DENTALIUM-FISSIDENTALIUM. 



This species is somewhat like D. zelandicum Sow., from New Zea- 

 land, British Museum, but in form is much stumpier, the ridges are 

 closer and the shell thinner. Than D. grande Desh., " Japan," 

 British Museum, it likewise is stumpier in form ; the ridges are less 

 strong, the furrows less marked, the circular striae less sharp ; in D. 

 amphialum the longitudinal ridges die out, while in D. grande they 

 continue equally strong 



D. CANDIDUM Jeffreys. PL 15, figs. 39, 40 ; pi. 8, figs. 27, 28, 29, 30. 



Shell rather large and solid, the earlier third or half moderately 

 curved, the remainder nearly straight : of a drab or ashy-gray color, 

 the young sometimes brilliant white ; glossy. Sculpture, of numer- 

 ous (44-48) low, rounded and rather flattened riblets parted by im- 

 pressed linear grooves ; toward the apex the riblets or striae become 

 higher, narrower and parted by intervals as wide as themselves, and 

 toward the aperture the riblets become lower and nearly or wholly 

 disappear; oblique, irregular, sinuously circular growth-lines replac- 

 ing them. Aperture decidedly oblique and nearly circular. Apex 

 small, with circular orifice, simple or with a slight encircling ledge 

 and a notch or slit on or near the convex side. 



Length 74, diam. at aperture 8, at apex 1 mill. 



Length 76, diam. at aperture 9, at apex 2 mill. 



Length 88, diam. at aperture 10 mill. 



Northern and eastern Atlantic and Bay of Biscay, 410-1750 fms. 

 (Valorous Exped.) ; west of Ireland, 664-1476 fms. (Porcupine 

 Exped.) ; Western Atlantic from off Nantucket southward to the 

 Carolina coast in 843-1309 fms. (U. S. Fish Commission) ; Gulf of 

 Mexico near Jamaica, etc. ; southern west Atlantic, 240 miles E. of 

 Rio Janeiro, 641 fms.; 90 miles N. of Ceara, Brazil, 1019 fms. 

 (Albatross). 



D. candidum JEFFREYS, Ann. Mag. N. H. (4), xix, p. 153 (1877) ; 

 P. Z. S., 1882, p. 658, pi. 49, f. 2 ; Proc. Koy. Soc. London, xxv, 

 pp. 184, 191, 199, no description (1876). DALL, Bull. M. C. Z., 

 xviii, p. 422 ; Bull. U. S. Nat. Mus., no. 37, p. 76 (1889) ; Proc. U. 

 S. Nat. Mus., xii, 1889, p. 294 (1890). D. solidum VERRILL, Trans. 

 Conn. Acad., vi, pp. 215, 276, 283, pi. 44, f. 16, (1884). Not D. 

 solidum Button, 1873. D. ceras DALL (not of Watson), Blake Gas- 

 tropoda, in Bull. M. C. Z., ix, p. 37 (1881) ; xviii, p. 425 (1889) ; 

 Proc. U. S. Nat. Mus., xii, p. 294 (1890). 



