THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[FOURTH SERIES.] 



No. 5. MAY 1868. 



XXXIX. — Contributions toward the formation of a correct Sys- 

 tem of Muscular Homologies. By ALEXANDER Macalister, 

 M.D., L.R.C.S., L.K.Q.C.P., Demonstrator of Anatomy, 

 Royal College of Surgeons, Ireland, one of the Honorary 

 Secretaries of the Royal Geological Society of Ireland *. 



The literature of comparative anatomy is teeming with me- 

 moirs and essays on that department of homology which treats 

 of the serial comparison of the muscles of the fore and hind 

 extremities in vertebrate animals. 



Almost every writer has originated an hypothesis of his own 

 (some of these being plausible and some fanciful), starting from 

 which he proceeds to work out details, some of which in all 

 theories are undoubtedly true ; but every author has differed 

 from his predecessors and successors in his reading of these 

 serial homologies. In the majority of these theories muscular 

 peculiarities have been regarded as subsidiary to osseous ar- 

 rangements, and many authors have deduced their ideas of 

 homotypical myology from the study of bones rather than 

 from the direct consideration of the muscles themselves and of 

 their relative positions, courses, and attachments. Such being 

 the present position of this branch of comparative anatomy, no 

 apology is needed for bringing forward any observations which 

 may perhaps have the advantage of novelty, and which may 

 elucidate in some degree the vexed question of serial homo- 

 logies. A great number of the misapprehensions into which 

 anatomists have fallen with respect to these homologies are due 

 to the fact that the individual components of the fore limb of 

 a limited number of animals have been compared directly with 

 those of the hind extremity, iiTCspective of the differences of 

 the work to which they may be devoted j but this is a mistake 

 in principle, and one from which we may free ourselves by 

 * Comraunicated by A. Carte, M.D., Dublin. 

 Ann, & Mag. N. Hist. Ser. 4. Vol.\. 23 



