IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 201 



towards the periphery ; ventral side strongly inflated ; equatorial periphery roughly 

 triglobular, distinctly lobate and sharply serrate, without a marginal keel ; axial 

 periphery subrounded or rather bluntly angular due to the slight compression of the 

 chambers towards the periphery ; chambers on the dorsal side are not all clear, but 

 appear to be 1 1 in number, arranged in 2 dextrally coiled whorls ; the initial chambers 

 are small, indistinct, and almost masked by the surface rugosity ; the last whorl is 

 composed of 3! large subglobular, compressed chambers which increase slowly in size 

 except for the last one which is slightly smaller than the penultimate ; on the ventral 

 side the chambers are 3^, subglobular and strongly inflated ; sutures on the dorsal 

 side short, curved and strongly depressed ; on the ventral side the sutures are radial 

 and strongly incised ; umbilicus reduced to an extremely narrow central pit from 

 which the apertrure starts and the ventral sutures radiate ; aperture interiomarginal 

 extraumbilical-umbilical, a large, crescentic arch extending almost to the periphery ; 

 wall calcareous, perforate ; surface rough, heavily nodose, with the nodes tapering 

 out in the form of stout spine-like projections, especially along the periphery. 



Dimensions of holotype. 



Maximum diameter = 0-39 mm. 



Minimum diameter = 0-34 mm. 



Thickness = 0-26 mm. 



Remarks. Globorotalia berggreni sp. nov. differs from G. esnaensis (Le Roy) in 

 its compressed test, smaller size, fewer chambers in the last whorl, subrounded to 

 subacute axial periphery, much narrower umbilicus and peculiar aperture. The 

 form described by Berggren (1960a, pi. 5, figs. 3«-c) as G. esnaensis (Le Roy) is 

 different from Le Roy's original description and figures, but may probably belong to 

 the present species, although it has more chambers, a more rounded axial periphery 

 and a more umbilical aperture. 



Globorotalia berggreni sp. nov. probably evolved from G. irrorata Loeblich & 

 Tappan by the development of a more tightly coiled, compressed test, a more spinose 

 surface, a much narrower umbilicus and a long slit-like aperture. On the other hand, 

 it might possibly have evolved from G. esnaensis (Le Roy) by the reduction in size of 

 test, its slight compression, and by the development of the very narrow umbilicus and 

 the long, slit-like aperture. 



This species is named after Dr. W. A. Berggren of the Geological Institute, Univer- 

 sity of Stockholm, Sweden. 



Holotype. P.45597. 



Paratype. P.45598. 



Horizon and locality. Holo- and paratype from sample No. 51, Gebel Owaina 

 section. 



Stratigraphical range. The species is a rare form in the upper part of the 

 G. velascoensis Zone, the G. aequa-G. esnaensis Subzone, of uppermost Paleocene 

 age. 



