392 



MANUAL OF ZOOLOGY. 



always in the form of fins that is, of expansions of the integu- 

 ment strengthened by bony or cartilaginous fin-rays. The 

 anterior limbs are known as the pectoral fins, and the posterior 

 as the ventral fins ; and they are at once distinguished from the 

 so-called " median " fins by being always disposed in pairs, 

 usually symmetrically. Hence they are often spoken of as the 

 paired 'fins. The scapular arch (figs. 164, 165) supporting the 



c u 



Fig. 165. Pectoral limbs of Fishes (after Owen). A, Cod (Morrhua inilgaris} ', B, 

 Angler (Lophius). ss Supra-scapula ; s Scapula ; co Coracoid ; r Radius ; u Ulna ; 

 cc Carpal bones ; f Fin-rays, representing the metacarpus and phalanges of the 

 fingers. 



pectoral limbs is usually joined to the skull (occipital bone), 

 and consists of the following pieces on each side: i. The 

 supra-scapula (ss); 2. The scapula (.$), articulating with the 

 former; and, 3. The coracoid (co), attached above with the 

 scapula, and united 'below, by ligament or suture, with the 

 coracoid of the opposite side, thus completing the pectoral arch. 



