.>40 upper cretaceous-lower tertiary foraminifera 



Main variation. 



i. Chambers 13-18, arranged in 2-3 tightly coiled whorls. 



2. Coiling is random, with a tendency to be sinistral (of 29 specimens studied, 12 



coiled sinistrally). 



3. Chambers in the last whorl 5-6, rarely 7. 



Remarks. The tendency towards the development of a partial pseudo-keel was 

 observed in specimens of G. uncinata uncinata Bolli from the Esna-Idfu region 

 (e.g. PL 19, figs. 2a-c) and can be seen on the holotype of Bolli (19576, pi. 17, figs. 

 13-15). This tendency was found to lead higher in the section to forms with very 

 well-developed, thick, nodose keels, which are here described as G. uncinata carinata. 

 This new subspecies is distinguished from G. uncinata uncinata Bolli, from which it 

 is believed to have evolved, by its thick, nodose keel ; flat, imbricate dorsal side ; 

 distinctly angular, axial periphery ; angular conical chambers on the ventral side, 

 and rougher surface. 



The marginal keel in G. uncinata carinata is very peculiar ; it is much thicker and 

 rougher than any known keel in the genus Globorotalia. The well-developed rugosity 

 does not allow one to see whether or not it is a true, imperforate keel, although it 

 seems quite distinct from the rest of the test. 



Holotype. P. 45634. 



Paratypes. P. 45635. 



Horizon and locality. Holo- and paratypes, from sample No. 36, Gebel 

 Owaina section. 



Stratigraphical range. The subspecies occurs as a rare form in the uppermost 

 part of the Middle Paleocene, (the upper part of the G. pusilla Subzone), to which it 

 seems to be restricted. 



Globorotalia uncinata uncinata Bolli 

 (PL 18, figs, xa-c ; PL 19, figs. 2a-c) 



19576 Globorotalia uncinata Bolli : 74, pi. 17, figs. 13-15. 

 ? 19606 Globorotalia uncinata Bolli ; Bolli & Cita : 30-31, pi. 32, figs. $a-c, ja-c. 



Description. (Described specimen, PL 18, figs xa—c.) Test small, almost 

 planoconvex, coiled in a very low trochospire ; dorsal side nearly flat, ventral side 

 strongly convex ; equatorial periphery subcircular to ovoid, distinctly lobate ; 

 axial periphery subrounded ; chambers on the dorsal side about 12-15, arranged in 

 2-2?, sinistrally coiled whorls ; the initial chambers are small, indistinct, and are 

 followed by crescentic, very slightly inflated chambers ; the last whorl is composed of 

 6, crescentic to nearly subcircular, slightly overlapping chambers which increase 

 rapidly in size ; on the ventral side the chambers are 6, subangular, roughly triangular 

 to subrounded, inflated to strongly protruding with the inflation increasing gradually 

 towards the last chamber ; sutures on the dorsal side strongly curved, depressed ; on 

 the ventral side they are very gently curved to nearly straight, radial and strongly 

 depressed ; umbilicus irregular in outline, roughly stellate, very narrow, moderately 

 deep and open ; aperture a narrow crescentic arch, interiomarginal, extraumbilical- 



