NO. 4 PLANKTONIC FORAMINIFERA — CIFELLI II 



Family GLOBIGERINIDAE Carpenter, Parker, and Jones, 1862 



Genus GLOBIGERINA d'Orbigny, 1826 



Globigerina bulloides d'Orbigny 



Plate 1 ; figures 1-3, 5 



Globigerina bulloides d'Orbigny, 1826, Ann. Sci. Nat., vol. 7, p. 777, Nos. 76, 

 17. — Bradshaw, 1959, Contr. Cushnian Found. Foram. Res., vol. 10, pt. 2, 

 p. 33, pi. 6, figs. 1-4.— Be, 1959, Micropaleontol., vol. 5, No. 1, pi. 1, figs. 

 15-17. — Banner and Blow, 1960, Contr. Cushman Found. Foram. Res., 

 vol. 11, pt. 1, p. 3, figs. 1, 4. — Parker, 1962, Micropaleontol., vol. 8, No. 2, 

 p. 221, pi. 1, figs. 1-8. 



Most of the specimens have bulbous chambers and broad, rounded 

 apertures that join in the center of the ventral side to form a large, 

 open umbilicus. The species, however, shows continuous gradation to 

 small compact forms with restricted apertures and reduced umbilical 

 areas (pi. 1, fig. 2b). These latter forms are relatively scarce but are 

 included in G. bulloides because of the continuous gradation. 



The final chamber in Globigerina bulloides and other species of 

 Globigerinidae shows considerable variation and, as noted by Parker 

 (1962, p. 246), sometimes covers the umbilicus and is reduced in size. 

 I agree with Parker that a bulla is often nothing more than a much- 

 reduced final chamber covering the umbilicus. A specimen of G. 

 bulloides with a well-defined bulla is figured here (pi. 1, fig. 5b). 

 Other specimens with the final chamber covering the umbilicus and 

 grading from bulla size to normal size were also observed. An effect 

 of the final chamber covering the umbilicus is that the aperture is 

 reduced to a narrow slit or is completely absent. 



Distribution. — Overall, Globigerina bidloides was observed to be 

 the dominant species in the shelf and slope waters. The highest fre- 

 quency was 70 percent at winter shelf station C. Along with other 

 species of Globigerina it diminishes in importance in the vicinity of 

 the Gulf Stream and was found to be rare or absent in most of the 

 Gulf Stream and Sargasso Sea stations. 



GLOBIGERINA PACHYDERMA INCOMPTA Cifelli 

 Plate 1, figures 4, 6 



Globigerina incompta Cifelli, 1961, Contr. Cushman Found. Foram. Res., vol. 12, 

 pt. 3, p. 84, pi. 4, figs. 1-7. 



This problematic form, which is characterized mainly by its sim- 

 plicity and paucity of distinctive characters, varies in the amount of 



