THE FAMILY TEXTULAEIIDiE 173 



segments. In deposits forming at the present time 

 it is not restricted in its depth. Miocene to Becent. 

 (Plate 9, fig. 0.) 



Genus Bifariiia, Paekee and -Tones. 



This is a dimorphous form, in \Yhich tlie earher 

 chambers are buhmine or boHvine and the later 

 ones uniserial. 



Example. — B. jwrrecta, Brady sp. (Bnlivina), 

 ' Quart. Journ. Micr. Sci.' X.S. vol. xxi. 1881, p. 57 ; 

 ' Eep. " Chall." ' vol. ix. 1884, p. 418, pi. Hi. fig. 22. 



This is a thin hyaline-shelled species, with more 

 or less coarse perforations in the shell- wall. It is 

 usually rare in marine dredgings, but was found in 

 abundance by Millett in his Malay samples. It is 

 never found in very deep water. Becent. (PL 9, 



fig. p.) 



Genus Bolivina, D'Oebigny. 



Test distinctly biserial, arrangement Textularian. 

 L. Cretaceous to Becent. 



Example. — B. textllarloldes, Eeuss, ' Sitzungsb. 

 d. k. Ak. Wiss. Wien,' vol. xlvi. 1862, p. 81, pi. x. 

 fig. 1. 



Of the regularly formed, few-chambered Bolivines 

 this species may be regarded as a central type. The 

 test is usually very finely arenaceous, especially the 

 fossil representatives. Its geological distribution 

 dates from the Lower Cretaceous period, and it 

 appears in many Tertiarij beds. B. textllarioides 

 inhabits shallow or moderately deep water at the 



