FORAMINIFERA OF THE ATLANTIC OCEAN. 



27 



BIGENERINA PENNATULA (Batsch). 

 Plate 5, fig. 4. 



"Orthoceratia Pupa," Soldani, Test., vol. 1, pt. 2, 1791, p. 99, pi. 108, figs. 

 D, E, F. 



Nautilus (Orthoceras) pennatula Batsch, Conch. Seesandes, 1791, No. 13, pi. 4, 

 figs. I3a-(L 



Bigenerina pennatula H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, 

 p. 373, pi. 45, figs. 5-8.— GoKs, i?ull. Mus. Comp. Zool., vol. 29, 1896, p. 44.— 

 Flint, Rep. U. S. Nat. Mus., 1897 (1899), p. 287, pi. 32, fig. 2.— Cushman, 

 Bull. 100, U. S. Nat. Mus., vol. 4, 1921, p. 127, pi. 25, figs. 3a, b. 



Vulvulina elegans d'Orbiqny, Ann. Sci. Nat., vol. 7, 1826, p. 264, no. 3. 



Grammostomum elegans Parker, Jones, and II. B. Brady, Ann. Mag. Nat. Hist., 

 ser. 4, vol. 8, 1871, p. 170, pi. 11, figs. 121, 123. 



Description.— Test much compressed, in the adult usually twice 

 as long as wide, the early biserial portion making up at least one-half 

 the test, broader than the following 1-4 chambers of the uniserial 

 portion, periphery acute, that of the early portion often pectinate; 

 chambers distinct, those of the uniserial portion somewhat inflated; 

 sutures of the early portion raised, confluent along the median line, 

 those of the uniserial part simple and depressed, wall fmely arenaceous, 

 in the biserial portion roughened, especially on the sutures and the 

 later chambers smooth; aperture in the early part textularian, in the 

 uniserial portion becoming much elongated, narrow, terminal, 

 central; color in the early portion yellowish-brown, the uniserial 

 chambers gray. 



Length up to 2 mm. 



Distribution. — This species is usually found in company with the 

 preceding. Its geographical distribution is very similar. In the 

 Albatross material it has been found at a large number of stations, 

 including one in the northern part of the Gulf of Mexico, four off 

 the southeast coast of the United States, and one in the Carribean, 

 off Yucatan. 



This species differs from the preceding in having the biserial portion 

 much more bluntly rounded, and often with a yellowish color, which 

 is lacking in B. capreolus. The biserial portion is also much broader 

 in comparison with its length. Some of the specimens show the 

 spiral arrangement of the early chambers, showing the relationship 

 of this genus to Textularia and Spiroplecta. 



Bigenerina pennatula — material examined. 



