BALL : MOLLUSCA AND BRACHIOPODA. 



359 



This is cue of the most elegant and abundant species of the region •with a geo- 

 graphical range of forty degrees in longitude and nearly 2000 miles iu latitude. 



Dentalium brevicornu Pilsbry and Sharp. 



Dentalium {Compressidens) hrtvlcornu Pilsbry and Siiarp, Man. Conch., 1897, 17, 

 p. 125, pi. 22, figs. 63, 64, 66. 



U. S. S. " Albatross," station 2807, near the Galapagos Islands, in 812 fathoms, 

 ooze, bottom temperature 38°.4 F. ; at station 2S08, iu 634 fathoms, sand, tem- 

 perature 40° (U. S. N. Mus. 122,809) ; and station 3431, oS" Mazatlan, Mexico, 

 in 995 fathoms, mud, temperature 37°-0. 



Very closely allied to the Atlantic I), pressum Pilsbry and Sharp, but the 

 tube increases more rapidly in caliber, and is decidedly less compressed on the 

 outer curve, according to Pilsbry, op. cit. 



Dentalium dalli Pusbrt and Sharp. 



Dentalium (Rhabdus) dalli Pilsbry and Sharp, Man. Conch., 1897, 17, p. 114, pi. 21, 

 fig. 46. 



U. S- S. " Albatross," station 3354, Gulf of Panama, in 322 fathoms, mud, 

 bottom temperature 46° P. U. S. N. Mus. 122,991. Also at station 3418, off the 

 coast of Mexico, near Acapulco, in 060 fathoms, sand, bottom temperature 39° F. ; 

 station 4654, off Aguja Point, Peru, in 101^6 fathoms, mud, temperature 3">°.5 ; sta- 

 tion 3346, off Tillamook, Oregon, in 786 fathoms, mud, temperature 37°. 3 ; station 

 3200, in the western entrance to the Santa Barbara channel, California, iu 265 

 fathoms, mud, temperature 43°. 1 ; and northward to Bering Sea, where it orcurs 

 north of Uualashka iu from 109 to 350 fathoms. 



Pilsbry notes fliat this species differs from specimens of D. prcfiositiii, which 

 sometimes approach it very nearly in size and form, by its extreme thinness and 

 fragiUty, beside lacking the apical striation of young I), pretiosum. 



Specimens from off Acapulco reacli a length of 66.0 with an oral diameter of 

 4.5 mm. 



