130 FORAMINIFERA 



Test in the early stages trihedral, angled, the sides 

 flattened ; chambers triserially arranged, adult chambers in a 

 loose spiral, five or more in a coil ; wall arenaceous with much 

 cement; aperture in the young as in Valvulina later developing 

 an opening in the plate-like tooth and in the adult a series of 

 small openings forming a cribrate plate. 



Tertiary and Recent. 



Genus LITUONELLA Schlumberger and H. Douville 



Plate 12, figures 23-26; plate 13, figure 23 

 Genoholotype, Lituonella roberti Schlumberger 



Lituonella Schlumberger and H. Douville, Bull. Soc. Geol. France, ser. 

 4, vol. 5, 1905, p. 297. 



Test conical, in the young a low coil of several chambers, later 

 becoming conical with annular chambers ; chambers labyrinthic, 

 extending clear across the test without increased surface divi- 

 sions; aperture cribrate, on the flattened face. 



Eocene. 



Genus COSKINOLINA Stache, 1875 



Plate 12, figure 27; plate 13, figure 24 

 Genoholotype, Coskinolina liburniea Stache 

 Coskinolma Stache, Verh. k. k. Geol. Reichs., 1875, p. 335. 



Test conical, the early chambers at least in the microspheric 

 form consisting of chambers in a low spiral, later with the 

 chambers forming annuli, roughly divided into chamberlets; 

 wall finely arenaceous with much cement; aperture cribrate on 

 the flattened outer face of the chamber. 



Eocene. 



This family forms a distinct group which if it were not for 

 the intermediate stages and those shown in the microspheric 

 form of the more complex genera would hardly be supposed to 

 have been derived from the Verneuilinidae and Textulariidae. 

 It is only by the study of the young of the microspheric form of 

 such types as Lituonella and Coskinolina that their relationships 

 to the other members of the family may be seen. The superficial 

 resemblance to the Buliminidae has caused some of the genera to 

 be placed with that group by some of the earlier workers. 



