DENTALIUM-ANTALIS. 45 



D. pretiosum Cpr., Moll. W. C. North Amer., in Rep. Brit. 



Asso. Adv. Sci. for 1856, pp. 296, 317 (name only ; " Central Amer- 

 ica, Dr. Sinclair in Brit. Mus."). — D. pretiosum Nutt., Sowb., Thes. 

 Conch., iii, p. 95, pi. 225, f. 57 (1860) ; Conch. Icon., xviii, pi. 7, f. 

 54 (1872).— Cpr., Rep. Br. Asso. for 1868, p. 560; (Smiths. Misc. 

 Coll., No. 252, pp. 31, 46).— Williamson, Proc. U. S. Nat. Mus. 

 XV, 1892, p. 194.— Keep, West Coast Shells, p. 113, f. 101 (1887). 

 — Entalis pretiosus Nutt., Lord, P. Z. S., 1864, p. 137 (method of 

 capture by aborigines). — Dentalium like entalis, Vancouvers Isl., 

 Cpr., Rep. Br. Asso., 1856, p. 296. 



^^ Dentalium (var.) Lidianorum," "Dentalium Q pretiosum Nutt., 

 Sby. var.) Indianorum," and " Dentalium Indianornm " Carpenter, 

 Rep. Brit. Asso. Adv. Sci. for 1863, pp. 612,648,683 (1864) ; Moll. 

 AVestern N. A., Smiths. Misc. Coll., no. 252, pp. 98, 134, 169.— D. 

 indianorimi^=pretiosum Stearns, Rep. U. S. Nat. Mus., 1887, pp. 

 315, 316, f. 8, 9, pi. 1, f 2 (use as money). — D. " preciosum " Cles- 

 siN, Conchyl. Cab., p. 15, pi. 4, f. 8 (1896).— Z). "pretiotmm" 

 James, Journ. Cincinnati Soc. N. H., viii, p. 36 (1885-6), 



D.politum Lamk., Middendorff, Beitriige Mai. Rossica, ii, p. 

 98 (not of Lam.). 



D. colambianum Clessin, Conchyl. Cab., vi. Heft x, p. [43], pi. 

 10, f. 4 (1896). 



Very similar to D. entalis, of the North Atlantic and perhaps 

 better ranked as a subspecies; but in general the Pacific shell is 

 larger, longer in proportion to the diameter, and whiter ; and these 

 differences, with the geographic separation, make it undesirable to 

 unite the forms. 



Clessin's D. columhianum is merely a short form of typical -pretio- 

 sum, utterly without specific or varietal characters diflferent from 

 pretiosum as ordinarily developed in British Columbian waters. 



Californian examples are decidedly smaller, and frequently lirate 

 toward the tip. This form has been called 



Var. iNDiANORUM by Dr. Carpenter, who describes it as "like 

 entalis, with very fine posterior strise." Specimens from Monterey, 

 San Pedro Bay, etc. are so sculptured. In the examples of this form 

 before me the apex is unslit, the anal orifice circular with thin walls. 

 Should these differences prove constant, indianorum may perhaps be 

 elevated to specific rank ; but in entalis the apical features are in- 

 constant. PI. 13, figs. 6, 7, 8 are normal indianorum ; figs. 4, 5 are 

 an older shell. 



