230 



TEETIAET VEETEBEATA OF THE EATtM. 



deltoid crest (d.) is enormously developed, forming the strongly convex sharp anterior 

 edge o£ three-fourths of the length of the shaft. The supinator ridge (s.r.) is greatly 

 developed as a sort of scroll-like flange which projects very strongly backwards 

 as well as outwards. The inner condyle (i.e.) is very prominent, and there is an 

 entepicondylar foramen {en./.). The coronoid fossa is small and shallow ; the olecranon 

 fossa is also small, but sharply defined ; there is no supratrochlear perforation. The 

 distal articulation consists of a prominent inner portion, projecting below the rest of 

 the surface, a gently rounded intercondylar ridge, and a narrow outer surface deeply 

 notched distally as in Lutra. On the whole, this humerus is very like that of Lutra and 



Text-fig. 75. 



Eight tibia of (?) Apterodon macrognathus, lacking epiphyses : A, from inner side ; B, from front. 

 en., cnemial crest ; m., m.' , deep impressions for muscle-attachments, h nat. size. 



still more like that of PotamotJieriwn, so that it is possible that the animal to which it 

 belonged may have lived a semi-aquatic life. The dimensions (in centimetres) of this 

 specimen are : — 



Length (from top of great trochanter) 21 



Width of proximal end 5-8 



,, middle of shaft (from side to side) 1'6 



,, „ „ (from before backwards) . . . 3'8 



„ distal end 6-3 



,, „ articulation 4-2 



M. 9357. Plaster cast of the above specimen. 



Made in the JSritish Museum. 



