N0.1237. SYNOPSIS OF THE LUCINACEA— BALL. 795 



DIPLODONTA (SPHiERELLA) VERRILLI Dall, 1899. 



From Marthas Vine>^ard, Mas.sachusctt.s, to North Carolina, in 15 to 

 69 fathoms. 



This is Diplodonia turgida Verrill and Smith, 1881, not of Conrad, 

 1818. 



LIST OF WEST AMERICAN SPECIES. 



DIPLODONTA (TORELLI Jeffreys var.?) ALEUTICA Dall, 1901. 



Southern part of Bering Sea, from the Pribihjf Ishmds to the Aleu- 

 tians, and eastward to the Shumagin Islands, in 3 to 13 fathoms. 



A chalky, subrectangular species, with coarse epidermis. The 

 young haye a smooth surface and dark gray periostracum. The 

 young of Torelli haye a yellow periostracum, profusely wrinkled. 

 The adults appear almost identical, though the regions occupied are on 

 opposite sides of the world. 



DIPLODONTA ORBELLA Gould, 1852. 



Kadiak Island, Alaska, to the Gulf of California, in 5 to 30 fathoms. 



Sj)hitreUa turn Ida (Conrad, Manuscript) Carpenter, 1863,^ is sj^n- 

 onjnnous. D. suhrugosa Philippi^ should be compared with it. 



The gills in this species'* are all deyeloped, the foot with a short, stout 

 stem, and distally subspherically bulbous; there are two entire 

 siphonal orifices, without siphons, the anal exhibiting a short yalye. 

 It is the habit of the animal to form a sort of nest of sand and adyen- 

 titious matter, cemented by mucus, with long tul)ular openings, the 

 whole of irregular form, but completely concealing the inmate. 



DIPLODONTA SUBQUADRATA Carpenter, 1855. 



Catalina Island, California, south to Panama, in 16 to 36 fathoms. 



More compressed and thinner than D. orhella^ and of a different 

 outline. In the description the edge of the excavated hinge plate has 

 been mistaken for a lateral tooth. It is not I). Hubquadrata Gabb 

 (=Z>. gcibbi Dall), 1873, from the Tertiar}- of Santo Domingo, West 

 Indies, but is probably referred to* by the name D. undata hy Car- 

 penter, 1857. 



DIPLODONTA PUNCTATA Say, 1822. 



From Magellan Straits northward to the island of Chiloe. See 

 Atlantic list. 



1 Not of Proc. Zool. Soc. London, 1856, p. 215. 



^Zeitsch. Mai., 1848, p. 183. 



^External and internal laminae, direct and reflected, with an appendix. 



* Mazatlan Catalogue, p. 103. 



