872 THE WHITE EIVEK FAUNA. 



exhibits a transversely oval humeral face of the head somewhat angulate at 

 a superior and an infero-Iateral extremity, which are diagonally opposed to 

 each other. Beyond the middle the shaft becomes wider, and is flattened 

 obliquely. 



The peduncle of the ilium has a triangular section, the anterior face 

 being the narrowest, and inclined at a little more than a right angle to the 

 interior face. It expands but little at the sacral extremity, and the crest is 

 very short. The external angle of the peduncle is very prominent and runs 

 into the anterior extremity of the crest, from which proceeds also the more 

 obtuse angle which is continuous with the pectineal line. A third longitudi- 

 nal angle is seen on the middle of the external side of the sacral extremity, 

 which is not continued on the peduncle. There is a prominent tuberosity 

 on the median or first-described angle on the peduncle, which may or may 

 not be homologous with the anterior inferior spine. There is no tuberosity 

 on the inner bounding angle of the inner face as is seen in Gymnoptychus. 

 The pubis leaves the ilium at right angles. Acetabulum nearly round. 



The femur has well developed great and little trochanters, and a third 

 trochanter, which rises from the shaft in line with the inferior border of 

 the little trochanter. The fossa of the great trochanter is well marked. 

 The head is not separated from the great trochanter by a deep emargina- 

 tion, and projects well within the internal face of the shaft. Its articular 

 surface is prolonged towards the great trochanter. Fossa Ugamenti teris 

 isolated. The distal extremity of the femur exhibits the superiorly pro- 

 longed patellar groove characteristic of this group of rodents. The condyles 

 are more than elsewhere produced downwards and posteriorly, and are well 

 separated. 



The spine of the tibia is rudimental, and the crest is very obtuse. The 

 inferior continuation of the latter forms a prominent reverted keel on the 

 proximal front of the shaft, which is deeply concave on its inner side. The 

 posterior face is also concave, and is separated by a laminar external bone 

 from the external side. The external border of the head is not deeply 

 notched as in Panolax. The fibula unites with the tibia on the proximal 

 part of the latter. The remainder of the shaft is smooth. The external 

 malleolus is large and at right angles to the long diameter of the distal end 



