• 



MCERITHEREUM GRACILE. 127 



Moeritherium gracile, Andrews. 



[Plate XVII. figs. 1-3.J 

 1902. Moeritherium gracile, C. W. Andrews, Geol. Mag. [4] vol. ix. p. 292. 



Type Specimen. — An imperfect sknll (PI. XVII. figs. 1, 2), including the palatal 

 region, associated with cervical, dorsal, and lumbar vertebrae ; Geological Museum, 

 Cairo. 



This species is distinguished from M. lyonsi by its comparative lightness of structure, 

 the narrowness of the palate, the smaller size of the upper molars and premolars, 

 particularly of m. 3, the strong development of the cingulum in these teeth, and by 

 the considerable inflation of the cranial region of the squamosal, which apparently 

 contains extensive air-sinuses. 



Form. & Log. — Qasr-el-Sagha beds (Middle Eocene) : north of Birket-el-Qurun. 



C. 10003. Cranial and palatal regions of skull -frith some vertebrae. Type specimen described in 

 Geol. Mag. [4] vol. ix. p. 292. Figured on PL XVII. figs. 1, 2. The palatal portion 

 (fig. 1) shows very well the great enlargement of i. 2, the extension forwards of the 

 maxilla (mx.) beneath the premaxilla {pmx.), the presence of a median anterior palatine 

 vacuity, the relatively small size of the teeth, particularly of the third molar (m. 3). 

 The cranial region (fig. 2) shows the comparative narrowness of the supraoccipital 

 escutcheon (soc.} (cf. PI. X. fig. 4 a) and the inflation of the upper part of the 

 squamosal («q.). The dimensions (in centimetres) of this specimen are : — • 



Distance from anterior end of snout to hinder border of palate . 21 



Width of palate opposite ifj. 2 2-8 



Approximate width of supraoccipital escutcheon 8'6 



Total width of occipital surface 18' 6 



The dimensions of the teeth are : — 



Length. Width. 



pm.2 2-2 1-8 



pm.2, 2 2-3 



pm. 4 2 2-1 (?) 



m. 1 2-3 2-3 



m. 2 2-4 2-5 



m. 3 2-8 2-4 



Length of molar and premolar series 13"7. 



Length of molar series 7"5. Length of premolar series 6'2. 



The vertebrae belonging to this skull include the centra of the axis and the five 

 posterior cervicals (two having part of the arch preserved), an anterior dorsal with part 

 of the archj also five other dorsal and two lumbar centra. 



The form of the axis, so far as it is preserved, is similar to that of the axis of 

 M. lyonsi. The centra of the posterior cervicals are oval in outline and slightly 



