OF THE SCArULA IN THE BATRA.CBTA. 



Example. 



Length of praecoracoid 10 units. 



,, scapula 3'9 „ 



,, „. (free upper aclge) 1-9 ,, 



,, ,, shaft 1-1 ., 



Breadth of „ (distal end) 2-6 „ 



(least) 1-8 ,'; 



Length of supra-scapula 9 - 2 ., 



Text-figure 4. 



201 



Pectoral girdle of Pipa americana. X2. 

 (a) from within ; (b) scapula from without. 



Aecifeea. 



In all the Arciferous genera in which I have studied the 

 scapula, its three main branches are all present, even if one or 

 more of them is reduced. The pars acromialis is more or less 

 separated from the pars glenoidalis by a cleft or foramen. 



DlSCOGLOSSID.E. 



As in Pipidce the scapula is greatly reduced. The pars 

 acromialis more or less overlaps the pars glenoidalis, so that the 

 cleft which separates them can only he seen when viewed 

 obliquely. 



Discoglossus Otth. 



D. pictus Otth. — .Scapula much reduced, its greatest length 

 only half that of the prsecoracoid. Shaft vestigial; pars 

 acromialis well developed, but shorter than pars glenoidalis; not 

 overlapped by head of prsecoracoid ; pars glenoidalis well de- 

 veloped, strongly depressed, the separating cleft pierced hori- 

 zontally. In eight skeletons of this species there appears to be 

 no individual variations. 



