BALL: MOLLUSCA AND BRACHIOPODA. 323 



U. S. S. " Albatross," station 4649, between the Galapagos Islands and Sechura 

 Bay, Peru, in S. Lat. 5° 17', and W. Lon. 85° 20', 2235 fathoms, mud, bottom 

 temperature 35°.4 F. U. S. N. Mus. 110,569. 



There is a minute chink behind the elevated edge of the columellar callus 

 anteriorly, but no umbilicus. This appears to be the largest shell from so great 

 a depth of water that has yet been collected ; the depths noted by the " Chal- 

 lenger " are somewhat inexact, owing to the use of hemp rope in dredging, and 

 nearly all excessive ; but taking thera at their face value, a Deutalium, a Chiton, 

 and a Pleurotomoid shell alone were obtained from greater depths. 



Oocorys (Benthodolium) pacifica Dall. 



Plate 4, figrure 7. 



Benthodolium pacijicum Dall, Proc. U. S. Nat. Mus., 1896, 18, p. 11. 



Shell resembling £. abyssorum Verrill and Smith, from the North Atlantic, 

 from which it differs by its much more elevated spire with the same number of 

 whorls, its smaller last whorl and aperture in proportion to the whole shell, its 

 more slender pillar and larger umbilicus, and esi)ecially by having its spiral sculp- 

 ture less crowded, and reticulated by narrow, flattened threads overrunning the 

 spirals and in harmony with the lines of growth. Lon. of shell, 30 ; of last whorl, 

 24; of aperture, 20; max. diam. 20 mm. 



U. S. S. " Albatross," station 3375, near Malpelo Island, Gulf of Panama, in 

 1201 fathoms, ooze, bottom temperature 30°. G F. 



U. S. N. Mus. 123,031. 



The operculum is narrower and less spiral than that of the Atlantic species. 



A fragment probably belonging to this species was also dredged at station 

 3386, in 1067 fathoms, globigcrina ooze, bottom temperature 37° F. 



The fine reflected outer lip of this species is obscurely ribbed like that of 

 Eudolium, but the difference in the nuclear shell and in the operculum are quite 

 sufficient to make the distinction between them easy. 



At station 3122, off Aeapulco, Mexico, in 141 fathoms, mud, bottom temperature 

 53°.5 F., a number of larval shells were obtained which appear to belong to a young 

 stage of a species of Uoliidae ; even the genus cannot with our present knowledge 

 be definitely determined. 



Cif-pracidae. 



TRIVIA GuAY. 

 Trivia atomaria Dall. 



Flate 12, flKurcs 8, 10, 11. 



Trivia atomaria Dall, Nautilus, Aug., 1902, 16, p. 43. 



Dredged in Panama Bay in 1888, in 18 fathoms, muddy bottom. U. S. Nat 

 Mus. 109,206. 



This is one of the smallest species known. 



