Farr.] lOO []SIay 15, 



convex, wliile the posterior border is only slightly rounded and is very 

 much thickened, a character that has been retained by the Equidae, Tylo- 

 poda, Pecora and Suina, but has been lost in the Tapiridae and Rhinocer- 

 otidfe. The spine of the scapula is very high and seems to extend nearly or 

 quite to the vertebral border. It is much nearer to the anterior border than 

 the posterior, thus making the prescapular fossa much smaller than the 

 postscapular. 



The spine becomes gradually more prominent towards the middle por- 

 tion, at which point it seems to have been highest and the edge was here 

 strongly retroverted as in Tapirus and Rhinoceros. From this point it 

 decreases in height towards the vertebral border. 



The acromion is styliform in shape, is compressed antero-posteriorly 

 and extends outward and downward, but does not quite reach the level 

 of the glenoid cavity. It resembles in shape that of the camel and 

 llama, but dift'ers from these in that they are more slender, more nearly* 

 perpendicular and extend nearly or quite to the level of the glenoid 

 cavity. The process gradually tapers towards the free end, which is 

 somewhat rounded. The neck of the scapula is very much constricted 

 and is comparatively long. The glenoid cavity is quite deeply ex- 

 cavated, is very slightly elongate antero-posteriorly and has a well-de- 

 fined rim. 



The coracoid process is strong, curves inwardly and is slightly 

 retroverted. 



Measurements of Scapula. mm. 



1. Extreme length 136 



2. Width of neck 18 



3. Width of distal end 32 



4. Extreme width 74 



5. Width at highest point of spine 74 



6. Width of supra-spinous fossa here 25 



7. Width of infra-spinous fossa here , 45 



Measurements of Scapula of Equus* mm. 



1. Extreme length 414 



2. Width of neck 73 



3. Width of distal end 107 



4. Extreme width 18(5 



5. Width at highest point of spine 14G 



6. Width of supraspinous fossa here 48 



7. Width of infra-spinous fossa here 93 



These measurements show the scapula of M. bairdi to have been pro- 

 portionately more expanded superiorly than that of the horse and at the 

 same time the neck is proportionately more contracted than in the latter. 



*No. 338, Princeton CoU. 



