IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 223 



out gradually upwards in the section, dying out completely in the overlying G. 

 aequa-G. esnaensis Subzone. 



Globorotalia perclara Loeblich & Tappan 

 (PL 21, figs. 2a-c) 



1957a Globorotalia perclara Loeblich & Tappan : 191-192, pi. 40, figs, ja-c ; pi. 41, figs. 8a-c ; 



pi. 42, figs. 4«-c ; pi. 45, figs, na-c ; pi. 46, figs. 3<z-c ; pi. 47, figs. 6a-c ; pi. 50, figs. la-c ; 



pi. 54, figs. 6a-yc ; pi. 57, figs, ^a-^c ; pi. 60, figs. $a-c. 

 i960 Globorotalia perclara Loeblich & Tappan ; Olsson : 46, pi. 9, figs. 1-3. 



Description. Test large, moderately inflated, coiled in a low trochospire ; 

 dorsal side almost flat, slightly imbricate in the early part, becoming gradually 

 inflated towards the last chamber ; ventral side moderately inflated although the 

 first two chambers are slightly flattened ; equatorial periphery roughly ovoid, 

 elongate, distinctly lobate ; axial periphery rounded ; chambers on the dorsal side 16, 

 arranged in 3 dextrally coiled whorls ; the initial chambers are small, slightly 

 flattened, increasing slowly in size and are followed by relatively larger, quadrangular 

 chambers which become crescentic towards the beginning of the last whorl, and 

 increase moderately in size ; the last whorl is composed of 6 large chambers which 

 are crescentic, imbricate and slightly compressed in the early part, globular and 

 inflated later, and increase moderately in size ; on the ventral side there are 6 large 

 chambers which increase gradually in size and degree of inflation ; sutures on the 

 dorsal side curved, depressed in the early part, becoming almost straight, radial and 

 strongly depressed later ; on the ventral side the sutures are straight, radial and 

 strongly incised ; umbilicus small, deep and open ; aperture a long, crescentic arch, 

 interiomarginal, extraumbilical-umbilical ; wall calcareous, perforate ; surface on 

 the dorsal side rough, papillose in the early part, smooth to very delicately papillose 

 later, heavily nodose on the ventral side. 



Dimensions of described specimen. 

 Maximum diameter = 0-44 mm. 

 Minimum diameter = 0-32 mm. 



Thickness = 0-25 mm. (of last chamber) 



Remarks. Globorotalia perclara was first described by Loeblich & Tappan (1957a) 

 from the Paleocene of the Gulf and Atlantic Coastal Plains. These authors also 

 considered the form previously described by Shifflett (1948) as Globigerina cf. 

 psendobulloides Plummer, from the Aquia formation of Virginia, to belong to the 

 present species. The specimens figured by Berggren (1960a) as G. perclara are 

 completely different from the types and should be considered separately. 



Globorotalia perclara is distinguished by its small to large, elongate test; its 

 tightly coiled, compressed early part, and globular, inflated later part; its distinctly 

 nodose, spinose ventral side, and almost smooth last chambers and rough early ones 

 on the dorsal side ; its curved dorsal sutures which are depressed in the early part, 

 and which become straight, radial, strongly depressed later ; its radial, strongly 

 incised ventral sutures ; its curved spiral suture which becomes strongly depressed 

 in the later part ; its narrow, deep umbilicus and its characteristic aperture. 



