FORAMINIFERA OF THE ATLAITTIC OCEAN. 67 



TRITAXIA LEPIDA H. B. Brady. 



Tritaxia lepida H. B. Brady, Quart. Journ. Micr. Soc, vol. 21, 1881, p. 55; Rep. 

 Voy. Challenger, Zoology, vol. 9, 1884, p. 389, pi. 49, figs. 12a, 6.— Millett, 

 Journ. Roy. Micr. Soc, 1900, p. 12, pi. 1, fig. 15. — HERON-ALLE^f and Ear- 

 land, Journ. Roy. Micr. Soc, 1908, p. 328. 



Description. — "Test triquetrous, elongate, broadest near the mid- 

 dle, tapering to a point at the aboral extremity, distal and rounded; 

 the tliree sides nearly equal, the angles sharp or subcarinate; texture 

 hyaline, aperture simple, consisting of a short tubular neck with 

 thickened lip, at the center of the terminal segment." 



"Length, l/80th inch (0.3 mm.)." 



Distribution. — Brady described this species from Challenger station 

 45, off the coast of North America, a little south of the latitude of 

 New York, at a depth of 1,240 fathoms (2,268 meters). This is the 

 only recent Atlantic record for this species. Millett records it from 

 a single station, and a single specimen from the Malay Archipelago, 

 and also records specimens from Challenger station 185 off Rame 

 Island, Torres Strait, 155 fathoms (283 meters). A comparison of 

 the figures given by Brady and that of Millett show considerable 

 difference in the two and it is probable that a further examination of 

 the specimens from the two areas will show that the one from the 

 Pacific is distinct. 



Genus GAUDRYINA d'Orbigny, 1839. 



Gaudryina d'Orbigny (type, G. rugosa d'Orbigny), in De la Sagra, Hist. Fia. 

 Pol. Nat. Cuba, 1839, •Foraminif^res," p. 109; M^m. Soc. G6ol. France, 

 ser. 1, vol. 4, 1840, p. 43; For. Foss. Vienne, 1846, p. 197.— H. B. Brady, 

 Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 377. — Chapman, The Foraminif- 

 era, 1902, p. 170.— Cushman, Bull. 71, U. S. Nat. Mus., pt. 2, 1911, p. 62. 



Heterostomella Reuss, Sitz. Akad. Wiss. Wien, vol. 52, pt. 1, 1865, p. 448. 



Description. — -Test free, composed of two distinct portions, the 

 earlier consisting of a series of chambers arranged triserially, followed 

 by a later consisting of a series arranged biserially; wall arenaceous, 

 varying much in coarseness in the different species; aperture variable 

 as in the various species of Textularia, either an opening at the base 

 of the inner margin of the chamber, between it and the wall of the 

 preceding chamber, or a perforation near the base of the inner margin, 

 often with a raised border, or in some species a terminal more or less 

 circular opening. 



The genus Gaudryina is evidently derived through triserial ances- 

 tors such as Verneuilina. Its later biserial development which is 

 very similar to that of Textularia in arrangement to chambers and 

 aperture is due to a reversion in its later development. There is some 

 difference in the apertural characters in the different species, some 

 being entirely Textularia-like, others being terminal. The genus is 

 known geologically from the lower Cretaceous to the present and 

 there is evidently much difference in the species in the different 

 geological periods and a uniting of the recent forms with those of the 



