DENTALIUM-L^VIDENTALIUM. 99 



a. Circular striae or rings toward smaller end. 



b. Transparent, with incised circular lines on smaller, 



smooth on larger half of shell; length 14 mill. N. 



E. Australia, anulosum, p. 101. 



b'. White, thin, narrow, circularly striate at apex ; 



length 22 mill., 11 times the diameter. Suez, 



subtorquatum, p. 101. 



a'. Smooth, nowhere conspicuously striate. 

 b. Quite arcuate. Antillean. 



c. White, arcuate, very slender; length 24 

 mill., 15 times the diameter, ensiforme, p. 101. 

 c'. White or pale salmon, rapidly tapering ; 

 length 61? mill., about 12 times the diam- 

 eter, callipeplum, p. 100. 

 b'. But slightly curved ; thin. Habitat unknown, 

 c. Greenish-yellow ; length 25 mill., 10 times 

 the diameter, translucidum, p. 99. 

 c'. Color?; very acute; longer and less curved 

 than translucidum; length 37 mill., about 

 12 times the diameter, ambiguum, p. 100. 

 c". Milky subtranslucent ; length 30 mill., 12 

 times the diameter, lacteum, p. 99. 



D. LACTEUM Deshayes. PL 19, fig. 1. 



Shell cylindrical, somewhat curved, very smooth and polished, 

 whitish, milky, subtranslucent. 



Smaller than entalis, and proportionally less in diameter, invari- 

 ably of a milky, subtransparent color, thinner than entalis and not 

 striated at the small end. Length 30, diam. 2? mill, at the base. 



No slit. (Desk.}. 



India (Desh.). 



D. lacteum DESK., Mem. Soc. Hist. Nat. Paris, ii, p. 362, pi. 16, f. 

 27 (not 28, as given by Desh.). Sows., Thes. Conch., iii, p. 98, pi. 

 225, f. 48. Not D. lacteum Costa, Faun. Reg. Nap., p. 37. Probably 

 not D. lacteum Dh., Tate, Tr., Proc. and Rep. Roy. Soc. S. Austr., 

 ix, p. 193. 



We have not seen specimens certainly referable to this species. 

 D. TRANSLUCIDUM Deshayes. PI. 19, fig. 5. 



Shell cylindrical, rather straight, polished, transparent, greenish- 

 yellow ; calcareous and solid, smooth. Length 25, diam. 2'5 mill. 



(Desk.'). 



Habitat unknown. 



