FOBAMINIFERA OF THE ATLANTIC OCEAN. 29 



BIGENERINA ROBUSTA Bradr. 



Bigenerina rohusta Brady, Quart. Journ. Micr. Sci., vol. 21, 1881, p. 53; Rep. Voy. 



Challenger, Zoology, vol. 0, 18S-1, p. r!71, pi. 45, figs. 9-16.— Flint, Rep. U. S. 

 Nat. Mus., 1897 (1899), p. 28(5, pi. 32, lig. 1. 



Description. — "Test elongate, subcylindrical ; early portion com- 

 pressed, and tapering to a blunt point, composed of a number of seg- 

 ments arranged, as in Texhdaria, in two more or less regular alter- 

 nating series: later portion cylindrical, convex or truncate at the 

 distal end ; consisting of numerous very short segments, the marginal 

 outline of which is often ventricose and irregular. Aperture in the 

 early stage Textularian in form and position; in adult specimens 

 terminal and porous." 



Length, ^ inch (4.2 mm.), sometimes more. 



Distribution. — Brady's records for this species are all in the Atlan- 

 tic, Challenger station 24, off Culebra Island, West Indies, 390 

 fathoms (713 meters); station 122, southeast of Pernambuco, Brazil, 

 350 fathoms (640 meters), and in one dredging in shallower water off 

 the Shetland Islands. In the Challenger volume, "Summary of 

 Results," it is recorded from station 23, off Sombrero Island, West 

 Indies, 450 fathoms (823 meters). Flint records it from Albatross 

 station D2150 in 382 fathoms (697 meters), off Old Providence 

 Island, south of Yucatan. I have not found in the Albatross material 

 any specimens which seem to belong to this species. The description 

 above is that of Brady. This species is peculiar in its aperture which 

 consists of several small openings instead of a single one. In this 

 respect it seems more like some of the older fossil forms than the 

 other recent species of the genus. 



Genus BOLIVINA d'Orbigny, 1839. 



Bolivina d'Orbigny (type, B. plicata d'Orbigny), Voy. Am^r. ^I6rid., vol. 5, 

 pt. 5, 1839, p. 61.— H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, 

 p. 416.— Chapman, The Foraminifera, 1920, p. 173.— ("ushman. Bull. 71, 

 U. S. Nat. Mus., pt. 2, 1911, p. 31. 



Description. — Test elongate, distinctly biserial throughout; wall 

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

 age in many species, ornamented by punctae, striae, costae, knobs, 

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

 usually symmetrical. 



As already noted in the Pacific work, the species of this genus for 

 the most part seem to be very local in their distribution. As stated 

 there this is especially true of species of tropical and subtropical seas. 

 A comparison of material from the eastern and western Atlantic, 

 from the Caribbean and the Gulf of Mexico, with that of colder parts 

 of the Atlantic and with the Pacific, shows that most of the species, 

 if carefully studied, are not widely spread. This was sliown by the 

 number of new species which Brady felt compelled to describe in the 

 Challenger Report. Most of the species are small and inconspicuous 



