FORAMINIFERA OF THE ATLANTIC OCEAN 95 



Soc. London, vol. 20, 1915, p. 590. — Chapman, Biol. Res. Endeavour, vol. 

 3, pt. 1, 1915, p. 11.— CusHMAN, Bull. 71, U. S. Nat. Mus., pt. 6, 1917, p. 

 9, fig. 7, in text. — Heron-Allen and Earland, Journ. Roy. Micr. Soc, 

 1924, p. 133. 



"Test free, thin, discoidal, planospiral; composed of a number of 

 convolutions of a narrow, slightly embracing tube. Convolutions 

 five to eight in number, the earlier whorls nonseptate, as in Cornu- 

 spira; those subsequently formed each divided into two or three 

 segments; the spiral suture and septa alike obscured externally by 

 the alar extensions of the investing wall over the lateral surfaces of 

 the shell. Aperture a simple terminal slit. Diameter, one-fiftieth of 

 1 inch (0.5 mm.) or less." 



There seems to be very little difference between this and Seguenza's 

 species. The Atlantic records include stations off Bermuda and West 

 Africa, but most of the records are from the shallow water of the 

 Indo-Pacific. 



Genus RENULINA Lamarck, 1804 



Renulina Lamarck (Genoholotype, Renulina opercularia Lamarck), Ann. 

 Mus., vol. 5, 1804, p. 354. — Cushman, Special Publ. No. 1, Cushman 

 Lab. Foram. Res., 1928, p. 166. 



Test in the early stages planispiral, in the adult chambers becom- 

 ing relatively shorter and broader, one side of the test nearly a 

 straight line, the opposite end extending back to the earlier coils, in 

 final stages of complete specimens the chambers extending back to 

 the earlier coils on both ends and becoming annular. 



Eocene. 



This genus which is a specialized one, greatly spreading in its 

 later development, and finally ending in annular chambers is an 

 end development which became extinct with the Eocene. 



Genus VERTEBRALINA d'Orbigny, 1826 



Vertehralina d'Orbigny (Genoholotype, Vertebralina striata d'Orbigny), Ann. 

 Sci. Nat., vol. 7, 1826, p. 283.— H. B. Brady, Rep. Voy. Challenger, 

 Zoology, vol. 9, 1884, p. 186. — Chapman, The Foraminifera, 1902, p. 

 97. — Cushman, Special Publ. No. 1, Cushman Lab. Foram. Res., 1928, 

 p. 168. 



Test with the early chambers planispiral, later ones in a rectilinear 

 series; aperture simple, a long narrow slit either at the outer end of 

 the chamber or somewhat laterally placed, typically with a definite 

 lip. 



Eocene to Recent. 



The species of this genus have the early stages planispiral, but 

 owing to the involute character it is often difficult to see the complete 

 stages without sections. The species are best developed in warm, 

 shallow waters of coral reefs. 



