THE SKULL OF OSSEOUS FISHES. 121 



interspace of the radius and ulna are sejiarated from the coracoids by 

 a sj^ace occupied by an aponeurosis ; and in the Wolf-fish the inter- 

 mediate carpals are almost divided by two opposite notches. The 

 ulna is perforated in all these fishes. The radius is of enormous size 

 in the Opal (^Lampris) and in the Flying-fish ; it is anchylosed with 

 the coracoid in the Silia-us, to give firmer support to its strong ser- 

 rated pectoral spine. I find both radius and ulna, which are ex- 

 tremely small, connate with the coracoid in a large Lophius {fig. 40. 

 54, 55). This condition probably occasioned them to be overlooked 

 by Geoffi'oy, Avhose figure of the bones of the pectoral extremity of 

 this fish* moreover represents the two long bones of the carpus, 

 (<6. 56, 56), which he calls 'radius' and 'ulna' upside down. 



m 



I' 



Bones of pectoral fin, Angler {Lophius). 



The ossicles called carpaJs are usually four or five in number, as 

 in the Cod tribe {fig. 19. 30. 56) ; they progressively increase in 

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

 the Parrot-fish ( Scarus) and the Mullets {Miigil). They are three in 

 number and elongated in the Polyjiterus {fig. 41. 56), but are reduced 

 to two in number, and more elongated in the Lophius {fig- 40. 

 56) ; thus they retain in this species and in the Sharks tlieir primi- 

 tive 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 Pla- 

 giostomes for broad and flat plates in ordinary Osseous Fishes. 



The rays representing the metacarpal and phalatigeal hones {fi'g. SO. 

 40. 57) 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 movement of 

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



* Annalcs du Museum, 1807, pi. 29. 



