SHOULDER-GIRDLE 



and the median symphysial bar of cartilage is lost ; this is the 

 case in Hetnisus. 



The scapula is always large and curved into transverse, 

 dorsally broadening blades, the dorsal greater portion of which, 

 the so-called supra-scapula, does not ossify but calcifies. 



It is very doubtful if the Anura possess a true sternum, if 

 by sternum we understand a medio- ventral apparatus which 

 owes its origin to the ventral portions of ribs. The so-called 



FIG. 5. Ventral views of the shoulder-girdles of various Anura. (Slightly enlarged.) 1, 

 Bombinator igneus, and 2, Bufo vulgaris, as examples of the arciferous type ; 3, 

 adult, 4, metamorphosing Rana temporaria, showing change from the arciferous 

 into the firmisternal type ; 5, Hemisus guttatum ; 6, Breviceps gibbosus ; 7, Cacopus 

 systoma. (5, 6, 7, after Boulenger. ) Cartilaginous parts are dotted; ossified parts 

 are left white. Cl, Clavicle ; Co, coracoid ; E, epicoracoidal cartilage ; H, humerus ; 

 M, metasternum ; 0, omosternum ; P, precoracoid ; Sc, scapula ; S. S, supra- 

 scapula. 



sternal apparatus of the Anura consists of two pieces. One, 

 anterior, variously named episternum, presternum, or omosternum, 

 rests upon the united precoracoids and extends headwards, being 

 either styliform or broadened out. Sometimes it is partly ossified, 

 with a distinct suture at its base ; this is the case especially in 

 the Firmisternia ; in many Arcifera the omosternum remains 

 cartilaginous and is continuous, without a sutural break, with 

 the cartilage of the precoracoids, indicating thereby its genetic 

 relation to the shoulder -girdle. Hence omosternum is the 



