FORAMINIFERA OF NORTH PACIFIC OCEAN. 



29 



a nearly smooth surface; aperture rounded, small, usually in the mid- 

 dle of the apertural 1'ace. 



Length 1-1.6 mm. 



Distribution. — Although this species has not heretofore been 

 recorded from the Pacific, specimens from Albatross station D4949, 

 in 110 fathoms on the coast of Japan, seem to belong to it. It 

 occurs with numerous other species of the colder water area, which 

 are similar to or identical with those of the northern Atlantic. 



This species at first sight might be taken for a Clavulina, but the 

 early chambers are biserial instead of triserial, as is the case in the 

 early development of Clavulina. The species differs from the preced- 

 ing in the early portion, which is here rounded, in B. nodosaria, being 

 much flattened, and in the union between the biserial and uniserial 

 portions, which are clearly distinguished in B. nodosaria by the differ- 

 ence in diameter of the test at that point, while in B. digitata the 

 point of union is hardly distinguishable, except by the sutures. 



BIGENERINA ARENACEA Bagg. 



Bigenerina arenacea Bagg, Proc. 

 figs. 4-6. 



U. S. Nat. Mus., vol. 34, 1908, p. 132, pi. 5, 



Description. — Test flattened, fairly large, composed of a series of 

 chambers arranged biserially, followed by a later portion made up of 

 broad, somewhat arched chambers arranged 

 uniserially, both portions much compressed; 

 in cross section elongate oval; sides well 

 rounded, not at all carinate; wall arenaceous, 

 varying in coarseness, smoothly finished; 

 aperture in the later portion an oval opening 

 in the middle of the apertural face. 



Length up to 3 mm. 



Distribution.— This species was described 

 by Doctor Bagg from several Albatross sta- 

 tions in the vicinity of the Hawaiian Islands. 

 I have examined 

 the type and other 

 specimens re- J0F 

 turned to the Na- ffc^ 

 tional Museum, 

 and have found FlG - 50 

 specimens from 



two other Albatross stations, station H2999, in 549 fathoms, and 

 station H2986, in 271 fathoms. A specimen from Nero station 990, 

 in 859 fathoms, off Guam, apparently belongs to this species. It is 

 somewhat more smooth and of finer material than usual, but this is 

 probably due to local conditions of the bottom. 



\ 



-Bigenerina arenacea. X 30. 



VIEW. 



a, front view; b, apertural 



