IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 219 



? 1957a Globorotalia aequo, Cushman & Renz ; Loeblich & Tappan (pars) : 186, pi. 59, figs. 



6a-c ; pi. 64, figs. \a~c ; ? pi. 60, figs, $a-c ; non pi. 46, figs. ya-8c, pi. 50, figs. 6a-c, pi. 55, 



figs. 8a-c (?). 

 ? 1961 Globorotalia triplex (Subbotina) ; Said & Kerdany : 330, pi. 1, figs. na-c. 

 ? 1962 Globorotalia (Truncorotalia) aequa simulatilis (Schwager) ; Hillebrandt : 134-135, 



pi. 13, figs. 6a-8c. 

 ? 1962 Globorotalia (Acarinina) quetra Bolli ; Hillebrandt : 144, pi. 14, figs. $a-c. 



Diagnosis. A Globorotalia with small strongly umbilico-convex test ; flat, 

 slightly imbricate dorsal side, and distinctly protruding ventral one ; extremely 

 narrow umbilicus, and high umbilical shoulder ; curved, imbricate dorsal sutures, 

 and radial, incised ventral ones ; crescentic chambers on dorsal side, elongated in 

 direction of coiling and increasing rapidly in size ; delicate marginal keel, and delica- 

 tely papillose surface. 



Description. Test small, planoconvex, umbilico-convex, coiled in a very low 

 trochospire; dorsal side flat, slightly imbricate ; ventral side distinctly protruding ; 

 equatorial periphery roughly ovoid, distinctly lobate with a delicately beaded 

 marginal keel ; axial periphery angular, acute ; chambers on the dorsal side about 12, 

 rapidly increasing in size and 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, crescentic chambers, which are strongly elongated in 

 the direction of coiling ; the last chamber constitutes about half the test ; on the 

 ventral side, the chambers are 3|, distinctly angular conical, strongly protruding ; 

 sutures on the dorsal side strongly curved, delicately beaded and very weakly raised ; 

 on the ventral side they are almost straight, radial and strongly depressed ; umbili- 

 cus extremely small, deep and open ; aperture interiomarginal, extraumbilical- 

 umbilical, a large, crescentic arch with a narrow delicate lip; wall calcareous perforate: 

 surface delicately but distinctly papillose with the papillae decreasing gradually 

 towards the last chamber. 



Dimensions of holotype. 



Maximum diameter = 0-30 mm. 



Minimum diameter = 0-22 mm. 



Thickness = 0-20 mm. 



Remarks. Globorotalia loeblichi sp. nov. is morphologically similar to both 

 Globorotalia lensiformis Subbotina, and Globorotalia quetra Bolli. It is distinguished 

 from the former by its much smaller size, less tightly coiled test, fewer chambers in the 

 last whorl, more lobate periphery, slightly imbricate dorsal side, less developed keel, 

 and less rugose surface. It differs from G. quetra Bolli in its much smaller size ; flat, 

 imbricate dorsal side ; less lobate periphery ; delicate, non-spinose keel, more angular 

 axial periphery, and delicately papillose, non-spinose surface. 



Loeblich & Tappan (1957a) described as G. aequa Cushman & Renz, from the 

 Paleocene-Lower Eocene of the Gulf and Atlantic Coastal plains of the U.S.A., and of 

 Mexico, forms with a marginal keel, although G. aequa does not have a keel. As can 

 be seen from their figures, these forms probably belong to the present species, to 

 G. quetra Bolli, and to other undescribed forms (see synonymy). Similarly, the form 



