IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 191 



1957 Globorotalia crassata var. aequo, Cushman & Renz ; Sacal & Debourle : 64, pi. 29, 



figs. 10-12. 

 1960& Globorotalia aequa Cushman & Renz ; Bolli & Cita : 17-18, pi. 31, figs. $a-c. 

 ? 1962 Globorotalia aequa Cushman & Renz ; Gartner & Hay : 560-561, pi. 2, figs. ia-2b. 



Description. Test large, coiled in a very low trochospire, strongly umbilico- 

 convex ; dorsal side almost flat, slightly imbricate, with the early whorls slightly 

 more elevated than the last one ; ventral side highly convex and strongly protruding ; 

 equatorial periphery ovoid, distinctly lobate and roughly serrate ; axial periphery 

 acute with the marginal serrations simulating a faintly developed nodose keel ; 

 chambers on the dorsal side n, arranged in 3 dextrally coiled whorls ; initial cham- 

 bers very small, slightly inflated, globigerine, increasing very slowly in size, and 

 masked by the surface rugosity ; the last whorl is composed of 3^, large, crescentic 

 chambers which increase very rapidly in size, the last chamber thus constituting 

 about one third of the test ; on the ventral side the chambers are 3^, large, strongly 

 inflated and distinctly protruding ; sutures on the dorsal side strongly curved, 

 slightly depressed ; on the ventral side they are radial, strongly depressed ; umbilicus 

 roughly rectangular, narrow, deep and open ; aperture interiomarginal, extra- 

 umbilical-umbilical, a long, roughly crescentic, wide arch, extending to the periphery; 

 wall calcareous, perforate ; surface highly roughened by long stout, spine-like 

 projections or granules, the roughness decreasing gradually towards the last chamber. 



Dimensions of described specimen. 

 Maximum diameter = 0-48 mm. 

 Minimum diameter = 0-34 mm. 



Thickness = 0-30 mm. 



Main variation. 



1. Chambers 9-12, arranged in 2^-3 whorls predominantly dextrally coiled 



(of 154 specimens chosen at random, 3 coiled sinistrally) . 



2. The last whorl is composed of 3-4 chambers (usually 3!) which increase very 



rapidly in size. 



Remarks. Globorotalia aequa was first described by Cushman & Renz (1942) as 

 a variety of G. crassata (Cushman) ; these authors briefly stated " Variety differing 

 from the typical in the much smoother surface, and the chambers, especially the 

 later ones, broader and more arcuate ". However, from their figures, it is clearly 

 seen that the form has a rough surface and a distinctly spinose periphery. 



Bolli (19576 : 75) stated that " No close morphologic or stratigraphic connection 

 is evident between Globorotalia aequa Cushman & Renz and the coarsely spinose 

 G. crassata (Cushman) from the middle to upper Eocene ", and thus he raised this 

 variety of Cushman & Renz to specific rank. He added, " A comparison of the 

 holotypes of G. aequa and G. lacerti Cushman & Renz clearly indicates that the latter 

 is a junior synonym ". The author is in entire agreement with Bolli's observations, 

 although it has to be clearly stated that G. aequa is characterized by its rough, 

 coarsely spinose, nodose surface, contrary to the impression given by Bolli's state- 

 ment and by that of Cushman & Rentz (1942). Again G. aequa is charaterized by its 



