43 



A milk-white, conspicuous species, slightly arcuate, eight angled at the apex, the 

 longitudinal striae very unequal down the body of the shcll, and entirely vanishuig before the 

 base, which is very smooth and round at the orifice. It is concentrically unequally Hrate; two 

 specimens (Melv.). 



I have compared the t\-pes in the British Museum and find them less tapering than 

 gtiadrapicale, while with the same length they have a greater diameter than in that species. 

 The apex is very wide having in one specimen a diameter of 1,5 in another of 2 mill. which 

 makes it very probable that the more attenuated foursided apex of the young shell has been 

 replaced by the octagonal part of the older shell. 



Subgenus Antalis H. & A. Adams 1854. 



1847. Entalis Gray, P. Z. S. p. 158. Not Entalis Sowerby 1839 = Pyrgopolon Montf. 18 10. 



1854. Antalis H. & A. Adams, Gen. Proc. Moll. I, p. 457. 



1894. Entaliopsis Newton & Harris, Proc. Malac. Soc. Lond. I, p. 66. 



1897. Antalis H. & A. Adams. PiLSBRY & Sharp, Man. of Conch., vol. XVII, p. ij. 



Shell circular or polygonal in section, sculptured with longitudinal ribs or striae at least 

 in the young, often without longitudinal sculpture in adults, or only so sculptured near the 

 apex; apex generally with a F-shaped notch at or near the convex side, or with a solid plug 

 and central short tube or orifice. Type D. entalis Linn. (P. & Sh.). 



I have entered here a description of D. entalis L. though the common form of that 

 arctic species does not occur in the Indopacific province. I have distinguished the single specimen 

 obtained at Stat 159 as an Indian variety as it could hardly be separated from entalis, differing 

 only in some minor points. 



*5i. Dentalium entalis Linné. PI. VI, figs 13, 14. 



1758. Dentalium entalis Linné, Syst. Nat. (10), p. 785; (12), p. 1263. 



1777. Dentalium entalis Linné. Pennant, Brit. Zool. IV, p. 145, pi. 90, fig. 154. 



1818. Dentalium entalis Linné. Lamarck, An. s. Vert. V, p. 345. 



1842. Dentalium entalis Linné. Reeve, Conch. syst. II, p. 6, pi. 130, fig. 3. 



1853. Dentalium entalis Linné. FORBES & Hanley, Nat. Hist. Brit. Moll. Il, p. 449, pi. 57, fig. 11. 



1865. Dentalium entalis Linné. JEFFREVS, Brit. Conch. III, p. 191, pi. 5, fig. i; V, fig. 55, fig. i. 



1873. Dentalium entalis Linné. SOWERBV, Conch. Icon. XVIII, pi. VI, fig. 40. 



1882. Dentalium entalis Linné. JEFFREYS, P. Z. S., p. 659. 



1885. Dentalium entalis Linné. WatsoN, Chall. Scaph. p. 5. 



1897. Dentalium entalis Linné. PiLSBRY & Sharp, Man. of Conch. XVII, p. 42, pi. 8, fig. 25. 



Dentalium striolatum Stimpson, Proc. Bost. Soc. Nat. Hist. IV, p. 114 (185 1). 

 Not D. striolatum Jeftreys, Watson or Sars. 

 Not D. striolatum Risso (1826). 



Diagnosis. Shell tapering, not much curved, often irregularly divided into segments by 

 the successive accretions of growth ; it is solid, opaque and glossy. Sculpture; slight concentfic 

 lines of crrowth, and occasionally a few indistinct and extremely fine longitudinal striae towards 

 the narrower end, these striae, when they occur, are not very numerous, and are only visible 

 with the aid of a magnifier; color ivory-white, with sometimes an ochreous stain on the narrower 

 nart, caused by an admixture of mud with the sand in which this species burrows: margin at 



