FORAMINIFERA OF THE NORTH PACIFIC OCEAN. 



23 



larly spiral with regularly 

 becoming highly irregular, 

 losing all trace of a spi- 

 ral arrangement; aper- 

 ture of the early cham- 

 bers typical, a slit be- 

 tween the ventral face of 

 the chamber and the pre- 

 ceding one ; in the irregu- 

 lar chambers several 

 apertures on the periph- 

 ery- 



formed chambers, following chambers 

 added finally in concentric rings and 



Diameter 0.38 to 0.52 

 mm. 



Fig. 27.— Discorbi3 irregularis Rhumbler. x 132 

 Rhumbler's type figure.) 



(After 



Distribution. — Rhumbler described this species from Chatham 

 Island. I have had no material that can be referred unquestionably 

 to this species, which may be a local one. 



DISCORBIS SUBFILOSA, new species. 

 Plate 6, fig. 2. 



Description. — Test strongly biconvex, less so ventrally, and um- 

 bilicate; chambers few in the final coil, rounded; sutures slightly 

 depressed, rather indistinct; wall ornamented by fine tubules extend- 

 ing through the much thickened wall below, with radiating lines from 

 the umbilicus. 



Diameter about 1 mm. 



Distribution. ^— Type-specimen (Cat. No. 9028, U.S.N.M.) from . 



The surface appearance of this species is very peculiar, arising 

 from the fine tubulation of the wall. 



DISCORBIS PULVINULINOIDES, new species. 



Plate 6, fig. 3. 



Description. — Test biconvex, somewhat flattened above, ventrally 

 rounded, umbilicate, carinate; chambers several, about seven in the 

 last formed whorl; sutures slightly depressed above, more strongly 

 so below; wall smooth above, ventrally with radiating lines extending 

 in toward the umbilicus. 



Diameter about 0.5 mm. 



Distribution. — Type-specimen (Cat. No. 9029, U.S.N.M.) from 

 Albatross station D4875, in 59 fathoms off Japan. 



Dorsally, this species is very much like certain species of Pulvinu- 

 lina, but the ventral view shows it to belong to Discorbis. 



70175°— Bull. 71, pt. 5—15 3 



