50 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 'jj 



Genus NUMMULITES Lai^arck, 1801 



Test coiled, biconvex, usually bilaterally symmetrical, composed of 

 numerous volutions. The chambers numerous and extending to the 

 umbo, each volution completely inclosing the preceding ones, the 

 periphery often keeled, aperture a simple V-shaped opening at the 

 base of the apertural face of the chamber. 



Genus OPERCULINELLA Yabe, 19 18 



Test in early development lenticular and close coiled, later develop- 

 ing an alar projection, supplementary skeleton and canal system well 

 developed. 



Subfamily 4. CYCLOCLYPEINAE 



Test flat with a thickened center, or lens-shaped, with two sets of 

 chambers, equatorial, forming a central plane of the test and lateral, 

 piled in columns at either side ; test strengthened by solid pillars 

 extending from the equatorial band to the surface ; sept^e double with 

 internal canals. 



Genus ORBITOIDES d'Orbigny, 1847 

 Test discoidal, equatorial chambers diamond-shaped. 



Genus ORTHOPHRAGMINA Munier-Chalmas 



Plate 16, fig. 6 



Test discoidal or stellate, equatorial chambers rectangular. 



Genus LEPIDOCYCLINA Giimbel, 1868 

 Plate 16, figs. 4, 5 

 Test discoidal, equatorial chambers typically hexagonal. 



Genus MIOGYPSINA Sacco 1893 

 Test irregularly discoidal, equatorial chambers rounded. 



Genus CYCLOCLYPEUS Carpenter, 1856 



Test thin, compressed, discoidal, usually of a single layer of 

 chambers, centrally thickened, chambers rectangular. 



