20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



Globorotalia cultrata (d'Orbigny, 1839) Parker, 1962, Micropaleontol., vol. 8, 

 No. 2, p. 235, pi. 5, figs. 3-5. 



The present specimens were compared with representatives of this 

 species from plankton tows collected in the Lesser Antilles region of 

 the Caribbean. Although the present Central Atlantic forms are 

 clearly identical with Caribbean forms, some small general differences 

 were noted, as follows : 



1, The Central Atlantic form, on the average, appears to be of 

 smaller size. 



2, In the Central Atlantic form the test is smooth with few or no 

 pustules on the surface. In the Caribbean form the test ranges from 

 smooth to rough, with many pustules or, occasionally, an additional 

 coating of calcite on the surface. 



3, The keel of the Central Atlantic form is thin and smooth with 

 little or no denticulation. In the Caribbean form the keel is more 

 variable and includes forms with thickened and crenulate keels. 



In general, the Central Atlantic form is simpler and shows less 

 variation than the Caribbean form. 



Distribution. — This species was observed mostly in the Sargasso 

 Sea stations. The highest frequency was recorded in the summer at 

 station KK (7 percent). However, most of the records were 1 percent 

 or less, suggesting that the stations occupied are beyond the optimum 

 range of G. menardii. It was particularly scarce in the stations from 

 the winter and spring traverses. 



GLOBOROTALIA TRUNCATULINOIDES (d'Orbigny) 



Plate 6, figures 1, 2; text figure 3 



Rotalina truncatnlinoides d'Orbigny, 1939, in Barker-Webb and Berthelot, Hist. 



Nat. lies Canaries, vol. 2, pt. 2, Foraminiferes, p. 132, pi, 2, figs. 25-27. 

 Globorotalia truncatulinoides Bradshaw, 1959, Contr. Cushman Found. Foram. 



Res., vol. 10, pt. 2, p. 44, pi. 8, figs. 7, 8.— Bf, 1959, Micropaleontol., vol, 5, 



No. 1, pi. 1, figs. 5-7. 



Globorotalia truncatulinoides is a distinctive and easily recognizable 

 species. In the adult form the test is high spired and has the shape of 

 a truncated cone, flattened on the dorsal side and with 5 chambers 

 visible on the ventral side. The periphery is subrounded in side view, 

 slightly keeled and denticulate. The aperture is a narrow, basal slit 

 that extends to a deep, narrow umbilicus; above the aperture there 

 is a well-defined lip. The projections of the lips of apertures on the 

 chambers surrounding the umbilicus form weak umbilical teeth. 



