FOBAMINIFERA OF THE NORTH PACIFIC OCEAN. 29 



Description. — Test adherent, flattened; early chambers distinctly 

 spiral, later ones less so, often irregularly annular in their arrange- 

 ment, more or less lobulated in the ventral face; periphery irregular, 

 often angular; wall very conspicuously perforated; early chambers 

 usually with a brownish color, later chambers grayish-white; sutures 

 depressed, often clearly marked on the dorsal face by a distinct baDd 

 of shell material ; apertures at either side of the chamber in the adult, 

 simple, each with a raised lip. 



Diameter 1-2 mm. or more. 



Distribution. — Rhumbler has recorded this species from shallow 

 water material from both Chatham Island and Laysan. I have had 

 it only from Nero station 990 in 859 fathoms, off Guam. 



PLANORBULINA ACERVALIS H. B. Brady. 



Plate 14, fig. 1. 



Planorbulina acervalis H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, 

 p. 657, pi. 92, fig. 4. — H. B. Brady, Parker, and Jones, Trans. Zool. Soc, 

 vol. 12, 1888, p. 227, pi. 46, fig. 11.— Flint, Rep. U. S. Nat. Mus., 1897 (1899), 

 p. 328, pi. 72, fig. 7.— Millett, Journ. Roy. Micr. Soc, 1904, p. 490 — 

 Rhumbler, Zool. Jahrb., Abteil Syst., vol. 24, 1906, p. 67. — Sidebottom, Mem. 

 and Proc. Manchester Lit. and Philos. Soc, vol. 53, 1909, p. 2, pi. 1, fig. 4; 

 vol. 54, No. 16, 1910, p. 27. 



Description. — Test typically adherent, composed of numerous 

 chambers, early ones spiral, later ones irregularly annular, those of 



the periphery lobulated, the newly 

 added chambers extending out- 

 ward a considerable distance be- 

 yond the preceding ones; ventral 

 surface often covered by a mass of 

 small acervuline chambers; wall 

 conspicuously porous ; apertures 

 lipped. 



Diameter up to 2.5 mm. 

 Distribution. — Rhumbler records 

 two specimens of this species from 

 fig. 32.-planoiuu™na ac^valis h . b . Brady. Laysan Island . I have had it from 

 X35. (adapted from Brady's figuke of the ]$ ero station 2071 in 271 fathoms 



TYPE ^ 



off the Hawaiian Islands, Nero sta- 

 tion 1466 in 234 fathoms off Guam, and Albatross H4882 off Blake 

 Reef in 248 fathoms, bottom temperature 48.8° F. in Colnett or Vin- 

 cennes Strait, off southern Japan. These are the three areas from 

 which most of the tropical species have occurred in the material I 

 have examined. It is essentially a species of shallow, warm waters. 



