NO. II FORAMINIFERA OF VENEZUELA GRAVELL 33 



The embryonic apparatus of a specimen 2.1 mm in length and 1.8 

 mm wide (pi. 6, fig". 9) peripherally located at the apex of the 

 test, consists of an initial globular chamber about 140 fi in diameter, 

 followed by two globular chambers about 120 fi in diameter. The 

 initial chambers are followed by four or five slightly smaller chambers 

 which are intermediate in character between the first two embryonic 

 chambers and the equatorial chambers and are cyclically arranged 

 around the inner side of the first three initial chambers ; walls of 

 embryonic chambers about 30 ju, thick. 



The equatorial chambers are diamond-shaped and vary in size, the 

 radial diameter almost always being the greater. The average size is 

 about 140 by 160 /x, though chambers half this size are found. The 

 walls are about 20 /x thick ; roofs and floors of the equatorial chambers 

 are pierced by numerous cribriform perforations, having a diameter 

 of about 3 fi. 



The equatorial chambers of the microspheric form near the em- 

 bryonic chambers are arcuate in form ; diameter about 40 ju, ; at a 

 distance of about 0.8 mm from the apex they become diamond-shaped ; 

 radial diameter about 160 /x; tangential diameter about 140 /x; at a 

 distance of about 2 mm from the apex, radial diameter about 200 fj- ; 

 transverse diameter about 130 //.; chamber walls about 20 jx thick; 

 roofs and floors perforated by numerous cribriform perforations 

 about 3 fi in diameter. 



In a vertical section of a broken specimen having a diameter of 

 1.52 mm and a thickness of 0.48 mm, the equatorial layer is 120 to 

 160 ,u high ; chamber spaces elliptical, from 60 to 100 /a high ; length 

 near embryonic apparatus about 40 /a; at a point about 1.5 mm from 

 the embryonic apparatus, length about 180 fx. The roofs and floors 

 of the equatorial layer are about 20 /x thick. 



There are about four layers of lateral chambers on each side of 

 the equatorial layer, irregular in arrangement and size, not arranged 

 in tiers. Dimensions of chamber spaces : Height, about 30 to 40 fx; 

 length, about 40 to 200 /x ; roofs and floors slightly arched, thickness 

 about 20 jx, perforated by numerous cribriform perforations. This 

 species has no pillars. 



Locality and geologic /lor/^cro;/.— These specimens were obtained by 

 M. N. Bramlette from well Rodriguez No. 23 from a depth of 2,482 

 feet, Ambrosia Field, District of Bolivar, Venezuela. 



The geologic horizon from which these specimens were obtained 

 is not definitely known, though it is probably middle or upper 

 Oligocene. 



