FAMILY 45. ORBITOIDIDAE 341 



tinct spiral. Equatorial chambers in a single layer near the 

 center, forming several layers near the periphery, those in the 

 same ring often slightly separated and arranged along radial 

 lines. 



Upper Cretaceous of Jamaica. 



Genus DISCOCYCLINA Gumbel, 1868 



Plate 56, figures 1, 2, 7; plate 58, figures 18-22 

 Genolectotype, Orhitulites jjratti Michelin. 

 Dificocyclina GtJMBEL, Abhandl. k. bay. Akad. Wiss., vol. 10, 1868, p. 109. 

 Rhipidocyclma Gumbel, Ibid., 1868, p. 110. 

 Orthophragmma Munier-Chalmas (pars), Etude du Tithon. du Cret. 



et du Tert. du Vicentin, 1891, p. 18. 

 Discocyclina H. Douville, Bull. Soc. Geol. France, 4th ser., vol. 22, 



1922, p. 64, numerous figs, in text and on plates. 

 Pseudophragmina H. DouviLLE, Bull. Soc. Geol. France, 4th ser., vol. 23, 



1923, p. 373, pi. 13, figs. 1-3. 



Test discoid, lenticular, thin or inflated, selliform, or stellate. 

 Surface granulate. Embryonic apparatus consists of a smaller 

 subglobular chamber partly embraced by a larger chamber. 

 Equatorial chambers of rectangular shape, usually radially 

 elongate, arranged in more or less definite concentric rings, the 

 radial walls of chambers of contiguous rings alternating in posi- 

 tion or aligned. Chambers of one ring communicate with the cham- 

 bers of adjacent rings by a row of lateral small apertures 5 to 

 7 \i in diameter, usually 2 to 4 in each row; the perforations in 

 the chamber roofs are very small, cribriform. Lateral cham- 

 bers greatly developed, usually composing most of the test. 

 Pillars usually well developed and terminate on the surface in 

 papillae or granulations of distinctive character of much value 

 in recognizing species. 



Danian to uppermost Eocene. 



H. Douville (op. sup. cit.) proposed the genus name Pseudo- 

 phragmina for Orthophragmina floridana Cushman as the 

 genoholotype and gave as its distinguishing features, first, the 

 degeneration of the radial chamber walls so that they do not 

 join the inner wall of the ring of chambers next beyond and in 

 places are represented by rows of granules; second, the radial 

 chamber-walls of one ring do not regularly alternate with those 

 of adjacent rings. I have had many specimens of Discocyclina 



