lvon] the hares and their allies 375 



spine, from the superior border to the edge of the glenoid cavity. 

 In the other rabbits the distance between the two superior angles 

 is contained but one and one-half times in the scapular length. 



ochotonid.e 

 (Plate XCVII, 5) 



The scapula of the Ochotonidse is of a quite different type from 

 that of the Leporidse. The general outline of the bone is also that 

 of a right triangle, but the right angle is very much rounded off 

 and the general appearance of the scapula is more oblique. The 

 acromion process is very long and slender, about twice the length 

 of the actual scapular spine. The metacromion is well developed, 

 and has about the same general proportion that it has in the Leporidse. 

 The posterior border of the scapula is long and more concave than 

 in the Leporida: ; the superior border is relatively longer and very 

 much rounded oft', so that it gradually merges into the anterior 

 border. The distance between the antero-superior and the postero- 

 superior angles is relatively greater in the pikas than it is in the 

 hares and rabbits, being contained but little more than once in the 

 length of the scapula taken along the attachment of the spine. The 

 supraspinous fossa in the Ochotonidse is relatively much narrower, 

 Avhen compared with the infraspinous fossa, than it is in the Leporidae. 



The scapula of Ochotona ladaccnsis differs somewhat from that 

 of the American species. The superior border is shorter and does 

 not merge so gradually into the anterior border, so that the antero- 

 superior angle is more pronounced. 



HUMERUS 

 Leporid.e 



The humeri of the Leporidse are all much alike in form and pro- 

 portions, and the humeri of the Ochotonidse differ but slightly from 

 them in these respects. The variations in this bone in the different 

 genera are few, hard to define, and apparently of little significance. 

 They are as follows : 



The groove that subtends the internal condyle is best marked in 

 inembers of the genus Lepns. It is well marked also in Syhnlagus, 

 Oryctolagns, and Pronolagus, but in Limnolagiis and Romerolagus 

 is much less developed and in Pcntalagus it is very slight. Brachy- 

 lagns occupies an intermediate position between these last two de- 

 grees of development. In Pentalagus the double trochlear surface 

 at the distal extremitv of the humerus differs from the same structure 



