IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 115 



dorsal side and the distinctly lobate periphery characteristic of the holotype. 

 Examination of topotype specimens, kindly presented by Dr. E. A. Pessagno, Jr., 

 showed clearly that they are more like the figures of the paratype of Pessagno than 

 those of the holotype. The limited number of specimens found in the present study 

 does not allow the evolutionary history of this subspecies to be followed although its 

 evolution from G. gagnebini Tilev is not excluded, despite Pessagno's statements. 



Hypotype. P. 45540. 



Horizon and locality. Figured specimen, from sample No. 16, Gebel Owaina 

 section. 



Stratigraphical range. Globotruncana gansseri dicarinata was first described 

 by Pessagno (i960) from the Rio Yauco mudstone formation of Puerto Rico where it 

 was stated to be common in the lower part of the Maestrichtian G. tilevi Subzone, 

 and to constitute a particular faunal zonule, the G. gansseri dicarinata Zonule. 



In the Esna-Idfu region, it occurs as a rare to common form in the Middle Maes- 

 trichtian G. gansseri Zone, and dies out completely in the basal part of the Upper 

 Maestrichtian G. esnehensis Zone. 



Globotruncana gansseri gandolfii subsp. nov. 



(PI. 5, figs. 2a-d) 



J 955 Globotruncana gansseri gansseri Bolli ; Gandolfi : 69-70, pi. 6, figs. 8a-c, text-fig. 11b. 



Diagnosis. A Globotruncana with small to large, quadrate, umbilico-convex 

 test ; weakly inflated chambers on dorsal side, slightly imbricate in last whorl ; 

 radial depressed ventral sutures, thin marginal keel slightly shifted towards dorsal 

 side ; rough surface. 



Description. Test large, roughly quadrate in outline, planoconvex, umbilico- 

 convex, coiled in a very low trochospire ; dorsal side almost flat and somewhat 

 imbricate although the chambers are weakly inflated and slightly overlapping; 

 ventral side strongly inflated and distinctly protruding ; equatorial periphery 

 roughly quadrate, moderately lobate, with a single, delicately beaded keel which is 

 slightly shifted towards the dorsal side ; axial periphery subangular, subtruncate ; 

 chambers on the dorsal side about 17 in number, arranged in 2I- dextrally coiled 

 whorls ; the initial chambers are exceedingly small, globular, slightly inflated and 

 almost masked by the surface rugosity ; they increase very slowly in size and are 

 followed by relatively larger, subglobular, slightly inflated chambers which increase 

 moderately in size ; the last whorl is composed of 4^, large, roughly ovoid chambers 

 which increase moderately in size, although the last chamber is slightly smaller than 

 the penultimate ; on the ventral side the chambers are 4^, large, subglobular, 

 strongly inflated and distinctly protruding ; sutures on the dorsal side slightly 

 curved, almost radial, raised and beaded, although the inflation of the chambers 

 makes them appear to be slightly depressed in part, especially towards the inner 

 whorl ; on the ventral side the sutures are straight, radial, and strongly incised 



