16 



BULLETIN 71, UNITED STATES NATIONAL MUSEUM. 



of France both call for an entirely different form of test from the 

 recent species usually passing under that name. In d'Orbigny's species 

 the test is distinctly flaring with concave sides, the sutures flush and 

 not limbate, and the broader apertural end of the test concave. 



The common recent species has a tapering test, but instead of a 

 broadly flaring later growth tends to increase in diameter less rapidly 

 as it approaches the adult condition. As a result the sides, instead 

 of becoming very concave are really convex, and rather strongly so. 

 The sutures as a rule are limbate and the chambers typically overlap 

 slightly, giving a test of greatly different appearance from d'Orbigny's 

 figure. 



After a study of a considerable series of foraminiferal material from 

 various European Tertiary and other deposits, especially from France, 

 I have been struck with the very considerable differences that appear 

 between the species of these fossil faunas and recent material. The 

 resemblances are for the most part small, and to unite any consider- 

 able number of these fossil species with the recent ones would mean 

 ignoring the very real differences that exist. To unite them on the 

 plea of great variation is not a position strengthened by a study of 

 large series of recent material. Therefore, it has seemed to me best 

 to call attention to certain of the apparent discrepancies that have 

 originated in this way and to try to correct them. 



TEXTULARIA RHOMBOIDALIS Millett. 



Textularia rhomboidalis Millett, Journ. Roy. Micr. Soc, 1899, p. 559, pi. 7, fig. 4. 



Description. — Test elongate, tapering, apical end rounded, aper- 

 tural end broadly rounded, in end view quadrangular or rhom- 



boidal, the sides slightly con- 

 cave, the sutures distinct, 

 somewhat depressed, curved; 

 wall calcareous, hyaline, 

 coarsely perforate; aperture 

 a deep rounded opening; color 

 white. 



Length 0.34-0.60 mm. 

 Distribution. — Not hitherto 

 recorded from the North Pa- 

 cific. One specimen was 

 found at Nero station 2042, 

 in 55 fathoms, near the Ha- 

 waiian Islands. From what 

 may be learned of the dis- 

 tribution of this species, it is apparently confined to tropical and 

 subtropical waters. 



Fig. 25.— Textularia rhomboidalis. X 75. 



a, APERTURAL VIEW; b, FRONT VIEW. 



