374 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45 



that Ronicrolagiis with the enlarged presternum would have clavicles 

 much larger than those in the other genera of the Leporidse, but 

 measurements show that the ratios of length of humerus to length 

 of clavicle in Ronicrolagiis is 3.20, in Oryctolagus 3.16, in Sylvi- 

 lagus 4.00. 



OCHOTONID.E 



(Plate XCVI, 2) 

 In the Ochotonidse the clavicle is very well developed, the ratio 

 of its length to that of the humerus is ^. The outer end, enlarged 

 and flattened, is connected by a ligament to the greater tuberosity 

 of the humerus. The inner end articulates directly with the extreme 

 anterior portion of the presternum. 



SCAPULA 



Leporid.e 

 (Plate XCVII, 1-4, 6-9) 



The general shape of the scapula of the Leporid^e is roughly that 

 of a right triangle, with the right angle rounded off, and directed 

 ►upward and forward. The acromion process is long and slender 

 and about half the length of the actual scapular spine. Coming 

 off at right angles to the acromion process and directed caudad 

 is a well developed pointed metacromion. 



The scapulae of the Leporidae fall into three not very strongly 

 marked groups : 



1. Large rabbits, members of the genus Lcpiis in which the 

 scapula is relatively broad, the superior border rather more convex, 

 the antero-superior angle more rounded, and the supraspinous fossa 

 relatively wider. 



2. Rabbits averaging smaller in size, members of the genera 

 Syk'ilagus, Oryctolagus, Brachylagiis, and Limnolagns, in which 

 the scapula is relatively narrower, the superior border straighter and 

 less convex, the antero-superior angle more pronounced and not so 

 gradually rounded ofif as in the genus Lcpiis. The supraspinous 

 fossa is relatively narrower. 



3. Romerolagus and Pronolagns have scapulae much alike and 

 differing from the scapulae of the other genera in being longer and 

 narrower. The posterior border is more nearly straight instead of 

 being concave as in the other two groups. The superior border is 

 straighter. The distance between the antero-superior and the 

 postero-superior angles is contained twice in the length of the 

 scapula measured along the inner surface at the attachment of the 



