in the esna-idfu region, nile valley, egypt 109 



Dimensions of holotype. 



Maximum diameter = 0-43 mm. 



Minimum diameter = 0-32 mm. 



Thickness = 0-22 mm. 



Variation. The main variation observed in specimens of G. fornicata globulo- 

 camerata is in the degree of globularity of the last chambers and the degree of surface 

 roughness. 



Remarks. All members of the G. fornicata group are generally characterized 

 by an early globigerine part, and later crescentic chambers which are strongly 

 curved and distinctly elongated in the direction of coiling. The present form, 

 however, represents a distinct type of this group in which the early globigerine 

 character extends to most of the final whorl, while the last one or two chambers still 

 keep the characteristic chamber form which is strongly elongated in the direction 

 of coiling. As all the other characters of the G. fornicata group are retained in the 

 present form, and as it has a slightly different stratigraphical range from G. fornicata 

 fornicata Plummer, it is here considered as a distinct subspecies. The name 

 G. fornicata globulocamerata describes the globular character of most of its chambers. 



G. fornicata globulocamerata is believed to have evolved from G . fornicata fornicata 

 Plummer, and into G. contusa sensu Troelsen, as suggested by the morphology and 

 stratigraphical distribution of these forms. 



Holotype. P. 45532. 



Paratypes. P.45533-34. 



Horizon and locality. Holotype, PL 14, figs. 2a-c, and paratype PI. 13, 

 figs, xa-c, from samples No. 4 and 3 respectively, Abou Saboun. 



Stratigraphical range. In the Esna-Idfu region, G. fornicata globulocamerata 

 occurs as a common to abundant form throughout the Lower Maestrichtian G. 

 fornicata Zone, fading out gradually upwards in the section and dying out completely 

 below the overlying G. gansseri Zone. 



Globotruncana fornicata manaurensis Gandolfi 

 (PL 13, figs. 2a-c) 



J955 Globotruncana fornicata manaurensis Gandolfi : 41, pi. 2, fig. la-c, text-fig. 9 (la-c ; 



2a-c) . 



Description. Test medium-sized, unequally biconvex, coiled in a low trocho- 

 spire ; dorsal side convex, moderately arched and slightly inflated, ventral side 

 almost flat, slightly raised and weakly inflated ; equatorial periphery subcircular, 

 slightly lobate, with two well-developed, closely spaced, thickened marginal keels ; 

 axial periphery subangular, subtruncate ; chambers on the dorsal side are not all 

 clear, but appear to be 18 in number, arranged in 3 dextrally coiled whorls ; the 

 initial chambers are very small, almost indistinct and are followed by slightly larger, 

 globular, inflated chambers which become roughly crescentic towards the last whorl 

 and increase moderately in size ; the last whorl is composed of 6 (5 + 1 abortive) 



