DOG-FISH. 15 



PECTOEAL FIN 



Is composed of a stem which is made up of jointed pieces of 

 •cartilage, which articulate with the" shoulder girdle by the inter- 

 mediation of three basal cartilages. The central stem is beset 

 on each side with lateral rays, which are jointed in a similar 

 manner as the stem. 



PELVIC GIRDLE 



Is formed of two coalesced cartilages. The venteral fins have 

 the same characters as that of the thoracic, with the exception that 

 the rays are arranged in a less complicated manner. 



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