1GG ANATOMY OF VERTEBRATES. 



plates in their interspace articulate directly with the coracoid. A 

 similar arrangement obtains in the Gurnards and the Wolf-fish ; 

 but the carpals in the interspace of the radius and ulna are sepa- 

 rated from the coracoids by a space occupied by clear cartilage ; 

 and in the Wolf-fish the intermediate carpals are almost divided 

 by two opposite notches. The ulna is perforated in all these 

 fishes. The radius is of enormous size in the Opah (Lampris), the 

 Cock-fish, fig. 38, and the Flying -fish ; it is anchylosed with the 

 coracoid in the Silurus, to give firmer support to the strong 

 serrated pectoral spine. Both radius and ulna are connate with 

 the coracoid in the Angler (Lophiits, fig. 102, 54, 55). 



The ossicles called carpals are usually four or five in number, 



102 



Coracoid and bones of pectoral fin, Angler (Lopkius) 



as in the Cod tribe, fig. 81, 56; they progressively increase in 

 length from the ulnar to the radial side of the carpus, especially 

 in the Parrot-fish (Scar us) and the Mullets (Mugit). They are 

 three in number and elongated in the Polypterus, fig. 103, 56, 

 but are reduced to two in number, and more elongated in the 

 Lophius, fig. 102, 56) ; thus they retain in this species and in the 

 Sharks, fig. 104, their primitive form of 'rays ;' but change to broad 

 flat bones in the Wolf-fish, just as the rays of the opercular fin 

 exchange that form in the Plagiostomes for broad and flat plates 

 in ordinary Osseous Fishes. 



The rays representing the metacarpal and phalangial bones are, 

 in the Cod, twenty in number, and all soft, jointed, and sometimes 

 bifurcate at the distal end. Their proximal ends are slightly 

 expanded and overlap each other, but are so articulated as to 

 permit an oblique divarication of the rays to the extent permitted 

 by the uniting fin-membrane, the combined effect being a move- 

 ment of the fin, like that called the ' feathering of an oar.' Each 



