44 



the anterior or broader end more or less jagged, owing to that part of the shell being newly 

 formed and consequently much thinner than other parts; at the posterior or narrower end it is 

 usually truncated in adult specimens, and furnished with a very short sloping and oblique pipe 

 or tubular appendage having a pear-shaped orifice; there is also occasionally at the point on 

 the convex side a notch or groove, in a line with the front or smaller part of the tubular 

 appendage, and this notch is rarely extended into a short and narrow slit or channel. 

 Length 37 — 42, diam. of aperture 4,5 — 5 mill. 



Distribution. Spitzbergen, Scandinavia, Iceland, and atlantic coasts of Europe, south 

 to Spain, 3 — 1750 fms. Coasts of Maine and Massachusetts north to Bay of Fundy. 



Var. indicuin n. var. PL YI, fig. 15. 



Stat. 159. o°59'.iS., I29°48'.SE. 411 Metres. Coarse sand, i spec. 



Very similar to D. entails but more slender, very glossy and entirely without longitudinal 

 sculpture. Apical notch on the convex side rather deep and extending into a very short 

 (0,04 mill.) slit. Tubular appendage very long (1,4 mill) slightly laterally compressed. Anterior 

 aperture very little oblique, dorso-ventrally compressed. 

 Length 26, lateral diam. of apert. 3,8, dorso-ventral diam. of apert. 3,4 mill. 



Subgenus Graptacme Pilsbry & Sharp 1897. 

 1897. Graptacme Pilsbry & Sharp, Man. of Conch., vol. XVII, p. 85. 



Surface sculptured with close, fine, deeply engraved longitudinal striae near the apex, 

 the remainder smooth; or rarely the striae persist half or all the length. Moderate sized or 

 small species, cylindrical in section, and white or nearly so. (P. & Sh.). 



D. usitatum is new to this group and bigger than the majorit)' belonging to it. 



The group is distributed over Antillean, Panamic and Indopacific regions. 



Key to species. 



Striae covering one seventh and less of shell; length 30 — 40 mill., about 12 — 14 



times the diam aciciiluui. 



Striae covering more than one seventh of the shell ; 



a. Length 45 — 65 mill., about 9 — i i times the diam itsitatuni. 



b. Length 40 — 50 mill., a.bout 20 times the diam anitissinium. 



52. Deiitalitim tisitatum E. A. Smith. PI. V, figs 6, 7, 8. 



1894. Dentaliuni usitatum Smith, Ann. & Mag. Nat. Hist. (6), XIV, p. 168, pi. 4, fig. 16, \6a. 

 1897. Dentalium usitatum Smith. PiLSBRV & Sharp, Manual of Conch., vol. XVII, p. 29, 

 pi. 10, figs. 68, 69. 



Stat. 88. o°34'.6N., 119° 8'.5 E. Celebes Sea. 1301 Metres. Fine grey mud. 6 Spec. 

 Stat. 211. 5°4o'.7S., I20°45'.5 E. Banda Sea. 1158 Metres. Coarse grey mud. 3 Spec. 

 Stat. 300. io°48'.6S., 123° 23'.! E. Timor Sea. 918 Metres. Fine grey mud. 2 Spec. 



