TELEOSTEAN CARTILAGINOUS PECTORAL GIRDLE. 



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ventral bar expanding on either side into a triangular plate perforated by 

 three foramina (fig. 4). These plates and the ventral bar represent the 

 coracoid regions fused. On each side is a small latero-dorsal scapular 

 process projecting in front of the fin-base ; while a longer postero-ventral 

 process extends backwards in the body- wall. At a little later stage, shown 



Fig. i. 



Clupea harengus, 30 mm. 

 Pectoral girdle and fins with muscles attached. 



Clupea pilchardus. 

 Cartilaginous skeleton of the pectoral fins and girdle. 



in fig. 6, tbe cross-bar becomes bent in the middle to form an acute 

 angle pointing forwards, and at tbe bend tbe cartilage becomes absorbed so 

 that the right and left halves soon are separated — a condition which, so far 

 as I have been able to make out, persists in tbe adult. 



Tbe development of the pectoral girdle in Teleosts has been studied by 

 Swirski (8) and Wiedersheim (10), and has lately been very completely 



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