34 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



chamberlets, and the distal wall is outwardly convex. Very near the 

 edge the chamber walls are more or less interrupted. Distance be- 

 tween successive walls from o.io to 0.05 mm. Another section, plate 

 27, figure 3, in an oblique plane shows that the equatorial chambers 

 when cut in the equatorial plane are either rhomboid or have an 

 outer curved wall and an inner pointed end. Communication between 

 adjacent chambers at the inner ends of the walls according to the 

 condition common in LepidocycUna is visible in many parts of the 

 section. 



There are three layers of lateral chambers except from the periphery 

 to about 0.5 mm back from it, where there are none. The chambers are 

 low, longer than high, in definite tiers, the tiers separated by thin 

 pillars. Length between 0.05 and o.io mm. 



LepidocycUna crassimargo appears to represent a species which 

 groups with LepidocycUna vaughani Cushman. Both have thickened 

 margins and diamond-shaped equatorial chambers. L. vaughani is a 

 coarser, thicker species, with well-developed pillars. Since it has 

 nephrolepidine embryonic chambers, L. crassimargo is tentatively 

 placed in the subgenus Nephrolepidina. 



LocaUty and geologic horizon. — North slope of La Piedra, north- 

 east of Jamaica, near Guantanamo, Cuba, U.S.G.S. locality no. 7664, 

 collected by N. H. Darton. Oligocene, probably upper. 



LEPIDOCYCLINA (NEPHROLEPIDINA) PIEDRASENSIS Vaughan, n. sp. 

 Plate 27, fig. 4 



Diameter of test about 10 mm, thickness through the center 1.5 mm. 

 Surface papillate ; the papillae rather thick and prominent, 0.20 to 

 0.25 mm in diameter, represent the emergent ends of pillars ; out- 

 wardly radiating fibers, which converge at steep angles, distinct. The 

 papillae are more crowded over the central part of the test, separated 

 by interspaces about o. 1 5 mm wide ; they are more distant toward 

 the periphery, interspaces 0.4 mm or more in width. 



Since there is only a vertical section the character of the embryonic 

 chambers cannot be fully ascertained. The embryonic apparatus is 

 rather large, composed of two chambers of unequal size separated 

 by a sloping wall. The entire apparatus is about i mm in diameter and 

 about half as thick in a vertical plane ; the bounding wall rather thick, 

 0.02 mm or somewhat more. 



The equatorial chambers increase in height very gradually and 

 rather slightly as the periphery is approached. 



The lateral chambers are low, considerably longer than high, 

 crowded, and irregular in size and outline. There are eight or nine 



