242 FORAMINIFERA 



The relationships of the Recent Indo-Pacific genera with 

 Hantkenina of the Upper Eocene are seen not only in the spinose 

 character of the large acicular spine in each chamber, and the 

 planispiral early development, but also in the apertural char- 

 acters, that of the specimen of Mimosina shown being very much 

 like that of Hantkenina with the two parts separated. The 

 family is related to the Heterohelicidae, 



FAMILY 31. BULIMINIDAE 



Test typically an elongate spiral, divided into chambers, in 

 the specialized genera biserial or uniserial or even monothala- 

 mous; wall calcareous, perforate; aperture loop-like or rounded 

 and terminal, usually with some sort of apertural tooth or spiral 

 connected with the interior tubular siphons connecting the aper- 

 tures. 



KEY TO THE GENERA 



I. Test, an elongate spiral, the spiral suture prominent. 



A. Test consisting of proloculum and long undivided tubular second 



chamber Terebralina. 



B. Test of numerous chambers, usually more than three to a whorl. 



1. Aperture with a broad base Turrilina. 



2. Aperture comma-shaped. 



a. Chambers in a single series Bidiminella. 



b. Chambers in a double series Rnhertina. 



3. Aperture rounded, terminal Buliminoides. 



II. Test triserial, at least in the early stages. 



A. Aperture comma-shaped. 



1. Chambers subglobular, test rounded in section. 



a. Chambers strongly involute at the base.. . .Glohohnlhmva. 



b. Chambers not strongly involute at the base, triserial 



throughout Bulimina. 



c. Chambers not strongly involute at the base, later biserial. 



Neohulimana. 



2. Chambers angled, test triangular in section Reussia. 



B. Aperture cribrate. 



1. Triserial throughout Chrysalidina. 



2. Young triserial, adult uniserial Chrysalidinella. 



C. Aperture with a collar typically open at one side and a prominent 



tooth Uvigerinella. 



