180 DR. C. "W. ANDREWS ON LOWER MIOCENE [Jlllie I914, 



side ; at its lower posterior border is the upper opening of the 

 astragalar canal, the lower aperture (/!) of which lies in a deep 

 pit between the posterior end of the ectal (ect.) and sustentacula!' 

 (sus.) facets for the calcaneum. The fibular facet is nearly flat, 

 and in the anterior half of its lower border it forms an obtuse 

 angle with the anterior part of the ectal facet ; posteriorly, the 

 two surfaces are separated by a deep groove, terminating anteriorly 

 in a foramen, a condition also seen in the astragalus of Apterodon. 

 The inner face of the body of the bone beneath the tibial surface is 

 concave, but ventrally it is produced into a considerable tuberosity. 

 The neck is long, and the head bears a convex navicular facet ; but 

 its borders are much broken and the actual form uncertain. The 

 elongated ectal facet is placed very obliquely, and is concave in 

 the direction of its length ; it is separated from the sustentacular 

 facet by a deep valley, which terminates postero-internally in the 

 astragalar foramen, while antero-externally it widens out. The 

 sustentacular facet is rhomboidal in outline, and is srentlv convex. 



Comparison with the astragali of other Carnivora shows that 

 this specimen is much like the astragalus of the Felidse. In these, 

 however, except in the Machserodontinse, there is no astragalar 

 perforation, and comparison with an astragalus of Smilodon shows 

 that in this genus, and probably therefore in other genera of 

 Machserodonts, the neck of the bone is much shorter than in the 

 specimen now described. Very considerable similarity to the 

 astragalus of Apterodon macrognathus from the Upper Eocene 

 of Egypt 1 is also noticeable. It seems, therefore, likely that this 

 bone may either belong to a big and probably primitive feline 

 Carnivore, or to a large Creodont surviving in this region after 

 the group had died out elsewhere. 



The dimensions (in centimetres) of the specimen are : — 



Greatest length G*3 



Greatest width 5*1 



Width of tibial surface (approximate) 3*3 



Order CHELONIA. 



Group Cryptodiea. 



This group of Chelonians is represented by portions of a large 

 and massive carapace and plastron (PL XXVII, fig. 4) belonging to 

 a species of Testudo. The most important fragment, from Bed 31, 

 at Kachuku, consists of the anterior half, of a plastron with parts 

 of the right axillary buttress and of the antero-lateral border of the 

 carapace. The plastron, so far as it is preserved, is very similar to 

 that of Testudo partialis, but belonged to an individual larger and 

 possessing a more massive shell than is found in this recent species. 

 On the right side the suture between the hvo- and hypq-plastra is 

 preserved, and if this suture is in the same relative position as in 



1 Brit. Mus. Catal. ' Tertiary Vertebrata of the Fayum ' 190G, p. 231. 



