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THE MYOLOGY OF AMIURUS CATUS 

 (L.) GILL. 



BY J. PLAYFAIR McMURRlCH, M. A. 



Professor in the Ontario Agricultural College. 



[Read before the Canadian Institute, April the 5th, 1S8&.] 



The group of the physostomous fishes shows many structural diver- 

 gences from the common type, and in the osseous and muscular sys- 

 tems this fact is especially noticeable. In no large group do we find 

 the structure identical throughout the various members, but varia- 

 tions occur sometimes in one, sometimes in another particular, ac- 

 cording to the natural conditions under which the animal exists. 

 The osseous and muscular systems being so closely related, one would 

 naturally expect to find great modifications of the one accompanied 

 by equal modifications of the other, the extraordinary development of 

 a muscle causing an extraordinary development of the parts to which 

 it is attached, and, vice versa, the modification of a bone for any 

 special purpose being accompanied by a suitable modification of the 

 attached muscles. 



Vetter 1 has given a detailed account of the myology of the head 

 and arches of Cyprinus, Barbus, Esox and Perca ; Cuvier 2 before him 

 a complete account of the musculature of Perca ; and similarly Owen * 

 and Stannius. 4 In the succeeding pages I propose giving an account 

 of the myology of Amiurus catus, a Siluroid, and comparing it with 

 that of other members of the Physostomi, with the object of showing 

 the coordinate modifications of parts and of deducing probable homo- 

 logies. I may state here that I am indebted to Prof. R. Ramsay 

 "Wright for information regarding the innervation of the various 

 muscles, he having studied this subject, so necessary in discussing 

 homologies, in connection with the nervous system of Amiurus. In 

 connection with the muscles of the head and arches, in drawing com- 



1 VetUr — Untersuchuugen ziir vergl. Anat. der Kienien, und Kiefer-Muskeln der Fische. 

 Th. II., Jen. Zeit. Bd. xii. 

 ' Cuvier et Valenciennes — Hist. Nat. des Poissons, Paris, 1828. 



* Owen — On the Anatomy of Vertebrates, Vol. I., London, 1866. 



* Stannius— Handbuch der Zootomie, Bd. I. 



