NOTES ON THE SALMO SALAR SPECIMEN — MORROW. 185 



The clavicle from its inferior edge to the extremity of its ante- 

 rior horn is in this specimen : — 2f inches in height ; 3f inches in 

 length, from posterior to anterior end. and measured on a line 

 through its centre ; the inter-clavicle is attached to it for about 1\ 

 inches, measured from the top of its anterior horn, and the shape 

 of its superior extremity nearly corresponds to that of the 

 inferior extremity of the inter-clavicle ; on its inner side, near its 

 posterior edge, there is slightly projecting from it a thin 

 bony plate, terminating at the lower edge of the clavicle to 

 which it is anchylosed, it has a narrow rounded end, this 

 unites with the posterior edge of the accessory bone — its lower 

 rounded end is close to it. The accessory bone arises about 

 midway on the posterior edge of the clavicle, at the junction of 

 the division of its thin posterior plates, and is anchylosed with 

 it ; it becomes gradually thicker for nearly one third of its length 

 and then decreases to its inferior end where it has the usual en- 

 largement for its attachment to the strong muscular tissue in 

 this part of the fish, its interior edge projects 1\ inches below 

 the clavicle, and its posterior edge f of an inch. This accessory 

 bone passes inside of the pectoral fin, and gives support to it ; 

 it is entirely different from that of the cod-fish in shape as well 

 as attachment. In the cod, as you will see by the specimen 

 (pectoral fin, clavicle, etc., shown,), it is a free bone, lying loosely 

 upon the upper posterior edge of the clavicle. 



The scapula joins at its superior extremity the upper edge of 

 the clavicle, and its inferior extremity the upper posterior divi- 

 sion of the coracoid bone ; its posterior inferior extremity is also 

 attached by cartilage to the posterior edge of the bones, which 

 represent the radius and ulna. 



The coracoid at its posterior extremity is divided. Its upper 

 edge is united with the scapula, as already mentioned ; its lower 

 limb, which is the longest, has its point attached to the inner 

 central ridge of the clavicle, and it is pierced by two foramina, 

 each of considerable size, one on either edge, outer and inner, the 

 latter being the largest and oval in shape ; the posterior edge of 

 this lower limb is united by a band of very thin bone, which fol- 

 lows on the one side its shape, and on the other the outline of 



