SnOULDER-GIRDLE 



25 



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

 case in Hemisus. 



The scapula is always large and curved into transverse, 

 dorsally broadening blades, the dorsal greater portion of wliich, 

 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 



Fio. 5. — Ventral views of tlie shoulder-girdles of various Anura. (Slightly enlarged.) 1. 

 limnbinator igneiis, and 2, Bufo vulgaris, as examples of the areiferous type ; 3, 

 adult, 4, metamorphosing liana tem.poraria, showing change from the areiferous 

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

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

 are left white. C/, Clavicle ; Go, coracoid ; E, epicoracoidal cartilage ; //, humerus ; 

 M, metasternum ; 0, omosternum ; /-*, precoracoid ; »■?<•, scajjula ; .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 -cfirdle. Hence omosternuin is the 



