Xect. II.] SHOULDER-BONES OP DUCKBILL. 



33 



girdle carries a pair of epi-puUc (or so-called Marsupial) 

 bones as in the Marsupials, in which they lie above or 

 within the pouch, so that their use is not very apparent, 

 for the " pocket " swings outside them. But their mor- 

 phology is evident, for the pelvis of the Salamander, 



l.r% 



—, St 



■MJ+S 



Tig. 3. — Shoulder-girdle and sternum (breast-tone) of OrnitfMrhynchus paradoxus, 

 two-thirds natural size, s.sc, supra-scapular region of scapula (shoulder-blade, sc) ; 

 m.sc, middle scapular region ; cl, clavicle ; i.cl, inter-clavicle, cr, ooracoid bone ; 

 e.cr, epiooracoid; gl, glenoid cavity, the head of upper arm-bone (humerus); 

 mi.s, manubrium (top or handle) of sternum ; st, sternum; x.s, xiphoid end of 

 sternum ; v.r, lower part of vertebral rib ; i.r, intermediate rib (as in Lizards) ; 

 s.r, sternal rib. 



and also, indeed, that of the Skate, shows similar out- 

 growths of the pubic region of the girdle. 



But it is in the front cincture, or shoulder-girdle, that 

 we see the most remarkable signs of ancientness in the 

 Prototheria. The scapula in them does not give off a 



