THE FAMILY LAGENID^ 193 



long slit down the ventral face of the final segment ; 

 chambers few. Recent. 



Example. — B. glabra, D'Orbigny, ' Forammif . 

 Foss. Yienne,' 1846, p. 63, pi. xxi. figs. 5, 6. 



This form is not often met with, and may 

 possibly be only an aberrant variety of Vaginuliiia. 

 D'Orbigny's specimen was obtained from the Adri- 

 atic. Beceiit. (Plate 10, fig. 0.) 



Genus Cristelhivla, Lamarck. 



Test planospiral in part or entirely ; complanate^ 

 lenticular, crozier-shaped or ensiform (elongate). 

 Ujjper Camhrlan to Recent. 



Examples. — C. crepidiila, Fichtel and Moll sp. 

 (Nautilus), ' Test. Micr.' 1798, p. 107, pi. 19, g-i. 



This is a complanate and somewhat elongate 

 form of the genus. It is common in fossiliferous 

 strata dating from the Lias, and at the present day 

 it is found in comparatively shallow water. Lias to 

 Beceiit. (Plate 10, tig. P.) 



C. hudensis, Hantken sp. (Bohiiliiia), ' Mitth. 

 a. d. Jahrb. k. ungar. Geol. Anstalt,' vol. iv. 1875 

 (1881), p. 58, pi. vii. fig. 1. 



The above species is a complanate, partiall}' 

 evolute form of Cristellaria, in which the primordial 

 chamber is just visible in the centre of the spiral 

 shell. The margin is carinate or sharply flanged, 

 as in the central type C. cnltrata, and of which there 

 are many varieties. C. hudeusis was obtained from 

 the Glavulina-szahoi beds of Budapest, of Eocene age. 

 (Plate 10, fig. Q.) 







