OF THE SCAPULA IN THE BATRACHIA. 203 



head of pr?ecoracoid are thin ahiiost to transparency, forming a 

 semicircular crest, the diameter of which follows the fiee upper 

 ed^re. 



The proportions of the scfipnla are remarkably stable within 

 the genus Bomhinator, and are highly charactei'istic. 



Alytes Wagl. 



A. obsteiricans Laur. — Scapula short, but less reduced than in 

 Discoglossus and Bomhinator. Upper border forming a semi- 

 circular crest thin to transparency, resembling BomhinatOQ- inaxi- 

 rmis in this respect. Shaft I'educed ; pars acromialis narrow, in 

 contact with head of pra?coracoid ; pars glenoidalis broad, 

 depressed, equal in length to pars acromialis ; the two over- 

 lapping, so that the dividing cleft is pierced horizontally and 

 only visible obliquely. 



Example. 



Ijength of praecoracoid 10 units. 



,, scapula (lower edge) 4"3 ,, 



„ „ (upper „ ) 3-6 „ 



„ „ shaft 2-2 ,, 



Breadth of ,, (distal end) 4"3 ,, 



Length of supra-scapula 10 ,, 



PELOBAXIUiE. 



In this family there is a wider generic diversity in the propor- 

 tions of the scapula, which is not, however, greatly developed in 

 any genus. In all, the glenoid cavity is excessively deep, some- 

 what undermining the pars acromialis, the lower edge of which 

 circumscribes it above. 



ScAPHioPUS Holbi-. 



*S'. solitarius Holbr. — Scapula well developed, longer than 

 praecoracoid ; as long as the supra-scapula. Proximal end well 

 developed, snbcircular. Shaft long, wedge-shaped ; ])a7'S acromialis 

 lai-ge, with crest-like upper border, lower border projecting over 

 and round glenoid cavity in a strong ridge ; pars glenoidalis 

 small, strongly depressed, the dividing cleft short and broa.d, 

 forming a small oval foramen in the glenoid cavity, pierced 

 vertically. 



Bxainple. 



Length of pfcecoracoid 10 units. 



,, scapula (upper or lower border)... 13 ,, 



„ shaft 9-4 „ 



Breadth of ,, (distal end) 5-3 ,, 



„ (middle) , 2-5 „ 



Length of supra-scapula 13 „ 



Proc. Zool. Soc— 1921, No. XY. 15 



