THE SKELETAL MUSCULATURE OF THE KING SALMON. 



By CHARLES WILSON GREENE and CARL HARTLEY GREENE, 

 Department of Physiology and Pharmacology, Laboratory of Physiology, University of AJissouri. 



GENERAL ARRANGEMENT OF THE SKELETAL MUSCULATURE. 



The general muscular structure of the king salmon has not previously been described. 

 One must therefore be guided by the general descriptions and comparisons as between 

 the musculature of the different parts of the body of the king salmon and that of other 

 fishes of related groups. 



The major amount of the muscle mass of the salmon is represented by the great 

 lateral muscles. These extend from the head and pectoral arch on either half of the body 

 straight along the sides to the base of the tail. Each great mass is grossly divided 

 longitudinally into dorsal and ventral portions, vertically into the well-known segments 

 or myomeres. Out of the extreme dorsal portion of the mass certain special longi- 

 tudinally arranged muscles have been developed. Along the mid-ventral line similar 

 longitudinal differentiations have occurred. In the head region the usual complex 

 differentiations of muscles have taken place. These muscles are undoubtedly derived 

 primarily from the great lateral muscle. 



In like manner, the muscle region at the base of the tail, the caudal peduncle, has 

 been differentiated into a number of definite and special muscles which produce the 

 complex movements of the caudal fin. 



The pectoral girdle and the pelvic girdle, together with the corresponding fins, 

 have a number of highly specialized muscles. Also the great median fins, the dorsal 

 fin, and the anal fin, each are supplied with a complex group of muscle filaments. . 



These great groups form the basis of the subdivisions which are followed in this 

 paper in describing the muscles in anatomical detail. In gross outline the groups are 

 as follows : 



Muscles of the trunk, the great longitudinal muscles 



Muscles of the head region. 



Muscles of the caudal fin. 



Muscles of the pectoral girdle. 



Muscles of the pelvic girdle. 



Muscles of the dorsal fin. 



Muscles of the anal fin. 



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