FORAMINIFERA OF THE NORTH PACIFIC OCEAN. 3 



arched opening between the base of the chamber and the preceding 

 one, often with a slightly thickened somewhat flaring lip. 



Length up to 1 mm. 



Distribution. — Brady records this species from six Challenger sta- 

 tions in the North Pacific at depths ranging from 95 to 3,125 fathoms. 

 Goes records it from eight Albatross stations in the western Pacific at 

 depths ranging from 770 to 1,832 fathoms. I have had it from sev- 

 eral Albatross and Nero stations off the Galapagos Islands, off the 

 Hawaiian Islands, off Guam and Japan, depths ranging from 323 to 

 2,256 fathoms. It has occurred usually as single specimens. 



There is some considerable variation in the amount of overlapping 

 of the chambers and a coincident variation in the form of the aperture 

 and its lip. 



Genus ALLOMORPHINA Reuss, 18SO. 



Allomorphina Reuss (type, A. trigona Reuss), Denkschr. Akad. Wiss. Wien, 

 vol. 1, 1850, p. 380.— H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 

 1884, p. 437. 



Description. — Test made up of a few ovate chambers, in a coil, 

 each chamber making up 120° of the volution so that but three 

 chambers are visible from the exterior; wall thin, translucent, punc- 

 tate; aperture a narrow slit at the base of the chamber. 



This genus is very similar to Chilostomella in its general characters 

 of the wall, but differs mainly in the arrangement of the chambers 

 in the coil, which in Allomorphina each make up 120° of the volution, 

 whereas in Chilostomella they take up 180°. 



ALLOMORPHINA TRIGONA Reuss. 



Plate 1, figs. 6-8. 



Allomorphina trigona Reuss, Denkschr. Akad. Wiss. Wien, vol. 1, 1850, p. 380, 

 pi. 48, figs. 14a-e— Schwager, Boll. Com. Geol. Italia, vol. 8, 1877, p. 26, 

 pi. 71— H. B. Brady, Quart. Journ. Micr. Sci., vol. 19, 1879, p. 67, pi. 8, 

 figs. 13, 14; Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 438, pi. 55, figs. 

 24-26.— Egger, Abh. kon. bay. Akad. Wiss. Miinchen, CI. n, vol. 18, 1893, 

 p. 305, pi. 9, figs. 3, 4.— Goes, Kongl. Svensk. Vet. Akad. Handl., vol. 25, 

 1894, p. 53, pi. 9, figs. 517-519. 



Description. — Test composed of several ovate chambers, coiled 

 each chamber making 120° of the volution and embracing so that 

 but three chambers are visible from the exterior, chambers longer 

 than wide, inflated, sutures somewhat depressed; wall smooth, con- 

 spicuously punctate, usually thin and translucent; aperture a narrow 

 curved opening at the base of the ventral margin of the chamber 

 between it and the previously formed adj acent chamber. 



Length about 0.40-0.60 mm. 



Distribution. — Brady reports this species from the Pacific. It has 

 not appeared in the material which I have examined. The figures are 

 from Brady. 



