SKELETON. 



499 



The branchial arches are divided into various parts, of 

 which the most interesting are the two superior pharyngeal 

 bones which lie in the roof of the pharynx and bear teeth, 

 and their counterpart, the inferior pharyngeal bone, which 

 lies on the floor of the pharynx, and is likewise toothed. 



The Limbs and Girdles. The dermal rays of the pectoral 

 fin are attached to four small brachial ossicles ; these articu- 

 late with a dorsal scapula and a more ventral coracoid; 

 both of these are attached to the inner face of a large 

 clavicle, which almost meets its fellow of the other side 



FIG. 1 68. Pectoral girdle and fin of Cod. (From 

 Edinburgh Museum of Science and Art.) 



y.r., Fin rays; b.o brachial ossicles ; cor., coracoid ; sc., scapula ; 

 cl., clavicle; p.cl., post-clavicle; s.cl., supra-clavicle ; p.t., post- 

 temporal. 



in the mid-ventral line of the throat. From the clavicle a 

 slender post- clavicle extends backwards and downwards ; 

 while a stout supra-clavicle extends from the dorsal end of 

 the clavicle upwards to articulate with a forked post- 

 temporal, which articulates with the back of the skull. It 

 must not be assumed that the elements of this girdle are 

 directly comparable to those of a higher Vertebrate, although 

 the nomenclature is the same. 



