80 PROCEEDINGS OF THE NATIONAL MUSEUM vol.77 



depressed, distinct; wall smooth, thin, almost transparent, initial 

 end sometimes with spines; aperture very finely radiate, produced. 



Length 0.40-0.75 mm.; breadth 0.30-0.60 mm.; thickness 0.25- 

 0.50 mm. 



Globulina ampulla has been neglected by later authors probably 

 because of its resemblance to Globulina gibba. It is different from 

 the latter in its pointed end, often with a spine and slightly depressed 

 sutures which are stronger at the base. 



Distribution. — Jones described this form from the lower Eocene, 

 Thanetian beds of Pegwell Bay, England. We have specimens from 

 the Eocene of France from the Lutetien of Parnes (Les Boves) and 

 Vaudancourt. A specimen from the Burdigalien inferieur of Moulin 

 de I'Eglise, Saucats, France, is also referred here with some question. 



GLOBULINA EXSERTA (Berthelin) 



Plate 20, figures 2 a-c 



Polymorphina exserta Berthelin, Mem. Soc. Geol. France, s6r. 3, vol. 1, 



1880, p. 67, pi. 4, figs. 22 a-23 6. 

 Polymorphina bucculenta Berthelin, M^m. Soc. Geol. France, ser. 3, vol. 1, 



1880, p. 58, pi. 4, figs. 16 a-17 b. 



Test more or less compressed, oval to ovate, initial end often pro- 

 duced; chambers inflated, earlier ones small, later ones much larger, 

 not much embracing, arranged in a nearly triserial series; sutures but 

 little depressed, distinct; wall smooth; aperture radiate. 



Length 0.55-0.60 mm.; breadth 0.30-0.35 mm.; thickness 0.23- 

 0.27 mm. 



Berthelin described two species of Polymorphina: P. exserta, and P. 

 bucculenta which appear to be closely related to each other. They 

 have the early chambers relatively small, the last two large, and show 

 no great difference in important characters. P. bucculenta is rather 

 unsymmetrical compared with the other, because the last chamber 

 does not extend down to the base. P. exserta has a produced initial 

 chamber. Such differences are not important as shown by Berthelin's 

 figures of two individuals of P. bucculenta which he considered to be 

 individual variation. 



We have many specimens of the present species from both European 

 and North American Cretaceous, and we are convinced that the species 

 is variable in the range shown by Berthelin's figures of the above cited 

 species. 



Distribution. — P. exserta is apparently limited to the Cretaceous and 

 is very common in the Lower Cretaceous. The localities of our speci- 

 mens are: Cretaceous, England, chalk marl, Saxon Cement Works, 

 Cambridge; Cambridge greensand, same locality. United States, 

 Goodland formation, near Fort Worth, Tex. 



