54 SMITHSONIAN MISCELLANEOUS COLLECTIONS N'OL. yj 



Genus TRILOCULINA d'Orbigny, 1826 

 Plate 15, fig. 2 



Test in its adult development consisting, as seen from the exterior, 

 of three visible chambers added in planes 120° from one another, the 

 third of each series added in the plane of the third preceding and 

 covering it. 



Genus ADELOSINA d'Orbigny, 1826 



Test in its early portion consisting of a large, laterally compressed 

 proloculum, followed by a second chamber making a complete coil 

 and covering the exterior of the proloculum, later chambers making 

 a half coil, variously ornamented, most frequently with longitudinal 

 costae. 



Genus BILOCULINA d'Orbigny, 1826 

 Plate 15, fig. 3 



Test in the adult, composed of chambers one-half coil in length, 

 in planes 180° from one another, only the two chambers last formed 

 visible from the exterior ; aperture usually broader than long, typically 

 with a bifid tooth. 



Genus FABULARIA Defrance, 1820 



Like Biloculina but the chambers with secondary divisions, aperture 

 cribrate. 



Genus NEVILLINA Sidebottom, 1905 



Plate 15, figs. 4, 5 



Test free, elongate, more or less pyriform, circular in transverse 

 section, the final single chamber completely embracing the previous 

 one ; aperture circular, complex, formed by numerous incurved la- 

 mellae, meeting centrally. 



Genus IDALINA Schlumberger and Munier-Chalmas, 1884 



Test subglobular, early stages as in Biloculina, final chamber covers 

 all previous ones ; aperture cribrate. 



Genus PENEROPLIS Montfort, 1808 

 Plate 15, fig. 6 



Test planospiral, at least in the early stages, whole test lenticular, 

 thick or much compressed, circular, crosier-shaped or cylindrical ; 

 surface smooth or the chambers longitudinally striate ; chambers 

 entire, not subdivided as in the following genera ; aperture in the 



