FORAMINIFERA OF NORTH PACIFIC OCEAN. 



31 



shaped test; wall thin and transparent; apertures numerous on the 

 peripheral wall, varying in size, and irregularly placed ; wall porous, 

 with numerous pores of good size more or less disposed in linear 

 series, each with the wall immediately about it thickened and often 

 slightly raised; color white, hyaline. 



The diameter of the test rarely exceeds 1 mm. 



Distribution. — This species seems to be rather rare, yet widely dis- 

 tributed throughout the warmer waters of the oceans. From the 

 Pacific it has been recorded by Brady from the coast of Korea and 

 from the coral reefs of Honolulu, in 40 fathoms; Bagg records it 

 from Albatross station D4174, near the Hawaiian Islands, in 735-865 

 fathoms. I have seen specimens from 

 three Nero stations, station 2042, in 55 

 fathoms, near the Hawaiian Islands, 

 station 201, in 1,033 fathoms, near 

 Midway Island, and station 1310, in 

 518 fathoms, near the Bonin Islands. 



D'Orbigny's original figure shows the 

 whole test without the biserial condi- 

 tion usually observed. Since the redis- 

 covery by Mobius of the species in 

 Madagascar sand, where d'Orbigny's 

 type material was collected, it is clear 

 that this is the species meant by d'Or- 

 bigny. The early portion was either 

 obscure in his specimen or else it rep- 

 resents a megalospheric specimen with- 

 out the biserial early stages. The later developed elongated cham- 

 bers may run entirely across the periphery of the test or it may take 

 two or even three chambers to complete the distance. 



Fig. 52.— Pavonlna flabelliformis. 



Young specimen hewed by trans- 

 mitted LIGHT. X 150. 



Genus BOLIVINA d'Orbigny, 1839. 



Bolivina d'Orbigny, (typo, B. plicata d'Orbigny) Voyage Amer. Merid., vol. 

 5, pt. 5, 1839, p. 61. — H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 

 1884, p. 416. - 



Description. — Test elongate, distinctly biserial throughout; wall 

 usually thin and hyaline in the young, but becoming thickened with 

 age in many species, ornamented by punctas, striae, costse, knobs 

 and spines, with carinse developed in some species ; aperture elongate, 

 usually wider at one end, usually symmetrical. 



This genus includes a large number of species, most of which are 

 of small size. In many cases the species seem to be very local in 

 their distribution, as shown by the work of the Challenger and again 

 in the present material. This is especially true of the species occur- 

 ring in fairly shallow water in the tropical and subtropical seas. 



