28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



the test, decreasing to about 90 ju near the rim. The papillae are 

 separated by a distance approximately equal to their diameter. 



The embryonic apparatus is composed of two subequal chambers, 

 initial chamber subspherical, about 210 by 280 ju, in diameter; second 

 chamber nearly hemispherical, 170 by 320 fx\ the wall between 

 chambers slightly curved toward the second chamber. On each side of 

 the junction of embryonic chambers is a chamber about 100 /x long and 

 50 ft wide. 



The equatorial chambers in horizontal section have curved outer 

 walls and pointed inner ends, the radial diameter only slightly greater 

 than the transverse diameter ; dimensions near the embryonic ap- 

 paratus about 50 jti ; near periphery about 60 jx. In vertical section 

 equatorial chambers are about 30 jx wide and 60 ix high near the 

 embryonic apparatus ; at the periphery about 40 /x wide and 140 /a 

 high; roofs and floors about 10 to 16 ju, thick, perforated by pores 

 from 2 to 3 /x in diameter. 



The lateral chambers in vertical section 20 to 40 /x high ; 40 to 

 200 ju, long. The smaller chambers are next to the equatorial layer 

 and increase in size toward the surface of the test ; as many as 16 

 layers over the center of the test in a tier 0.9 mm high, decreasing in 

 number toward the periphery. Large, cone-shaped pillars, irregular 

 in width interrupt the development of the lateral chambers. The 

 pillars are largest over the center of the test, where they attain a 

 thickness of more than 300 /x. 



Localities and geologic horizon. — Cotypes from locality 168 of 

 M. N. Bramlette's collection. Other localities at which this species 

 occurs are 960, 970, 1042, 11 16, and 1120, San Luis limestone, 

 middle Oligocene. This species appears to be restricted to the San 

 Luis limestone. 



L. {Lepidocyclina) sanluiscnsis resembles L. (Nephrolepidina) 

 inarginata (Michelotti) in form and surface ornamentation, but 

 differs in the character of the embryonic apparatus. The species is 

 named after the San Luis limestone of \'enezuela. 



Gorter and Van der Vlerk (25, p. 104) identified specimens of L. 

 (Lepidocyclina) sanluisensis, n. sp., from localities 11 16 and 1120, as 

 L. {Nephrolepidina) marginata. The embryonic apparatus, however, 

 is not that of a Nephrolepidina, but is that of Lepidocyclina s.s. 



LEPIDOCYCLINA (LEPIDOCYCLINA) sp. indet. (a) 



Thin sections of a limestone largely composed of mollusk fragments 

 contain a few rather unsatisfactory sections of a small Lepidocyclina. 



