IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 143 



well-developed marginal keels and the strongly protruding umbilical flange character- 

 istic of Quereau's form. They also conform well with the figures given by Tilev 

 (1951, 1952) whose thin section is almost identical with that of Quereau. However, 

 they differ from the forms figured by Cita (1948), Noth (195 1), Said & Kenawy (1956) 

 and Berggren (1962). The form figured by Barr (1962) as G. linneiana tricarinata 

 (Quereau) may possibly belong to G. tricarinata colombiana Gandolfi. 



Globotruncana tricarinata tricarinata is believed to have evolved from G. linneiana 

 linneiana (d'Orbigny) into G. area (Cushman) as previously suggested by various 

 authors (e.g. Vogler 1941, Gandolfi 1955, Bronnimann & Brown 1956 and Berggren 

 1962). 



Hypotype. P. 45562. 



Horizon and locality. Hypotype from sample No. 3, Abou Saboun section. 



Stratigraphical range. Globotruncana tricarinata tricarinata was first described 

 from the Campanian-Maestrichtian of Switzerland and was recorded from the same 

 level in various parts of the world. 



In the Esna-Idfu region G. tricarinata tricarinata is common in the Lower Mae- 

 strichtian G. fornicata Zone, decreasing gradually upwards in the section to die out 

 completely before the basal part of the overlying G. gansseri Zone. 



Globotruncana ventricosa White 



19286 Globotruncana canaliculata (Reuss) var. ventricosa White : 284, pi. 38, figs. ^a-c. 



? 1954 Globotruncana ventricosa White ; Nakkady & Osman : 90—91, pi. 19, figs. qa-c. 



1955 Globotruncana ventricosa carinata Dalbiez : 171, text-figs. 8a-d. 



1957a Globotruncana ventricosa White ; Bolli : 57, pi. 13, figs. \a~c. 



Remarks. Brotzen (1936) raised White's variety to specific rank although his 

 figures are completely different from those of White. The form described by Sigal 

 (1952) as G. lamellosa, from the Lower Maestrichtian of Algeria, appears from his 

 figures to be closely related to G. ventricosa White. However, examination of the 

 type specimens of G. lamellosa Sigal showed that the latter species is distinguished 

 by its unequally biconvex test, with a more protruding ventral side ; highly lobate 

 periphery ; two closely spaced keels, reduced to a single keel on the last few chambers 

 or chamber ; a well developed umbilical flange ; curved, raised, beaded dorsal 

 sutures and radial, depressed ventral ones ; and its very wide umbilicus. 



Dalbiez (1955) described two new subspecies of G. ventricosa White which he 

 named G. ventricosa carinata and G. ventricosa primitiva respectively, and thus 

 he changed the name of the present species to G. ventricosa ventricosa White. How- 

 ever, examination of the type specimens of these forms in Dr. Dalbiez's collection 

 showed that his G. ventricosa ventricosa White is actually G. concavata Brotzen, and 

 that although the figures were published under the first name, the slide carried the 

 name G. ventricosa concavata (Brotzen). Again, the holotype of G. ventricosa 

 carinata Dalbiez was found to differ from G. ventricosa White only in having a 

 slightly wider umbilicus and a more developed umbilical flange. Variation in such 



