THE BRACHIAL FLEXOR MUSCLES IN PRIMATES 



By A, Brazier Howell and William L. Straus, jr. 



Dvpaj'tment of Anatomy, Johns Hopkins University, Baltimore. Md. 



The investigator who undertakes to dissect the musculature of a 

 considerable number of mammals will at once find a diversity of con- 

 ditions in the brachial flexor muscles that may well puzzle him. Re- 

 course to the literature on the subject may shed but little light upon 

 his particular problems, for the reason that there is considerable 

 confusion and ambiguity in the manner in which authors dispose 

 of this group. 



The present writers found this state of affairs so unsatisfactory 

 that they undertook an investigation of the brachial flexors that was 

 sufficiently extensive to give them what they believe to be a proper 

 understanding of conditions. No attempt has been made to study 

 the situation found in a great number of genera, but fortunately 

 their own dissections have chanced to illustrate a number of differing 

 brachial details, which they believe to be sufficient for the purpose 

 stated. Primates only are herein considered, except that the inter- 

 esting condition in the opossum {Didelphis) is also mentioned, to- 

 gether with isolated details of representatives of one or two addi- 

 tional orders. The brachial flexors of these pertinent specimens 

 will first be described, and a discussion Avill then follow. 



Grateful acknowledgment is made to the officials of the United 

 States National Museum for the loan of four of the specimens dis- 

 sected, as well as for the numerous skeletons we have examined. In 

 addition, six of the specimens used and now designated by Johns 

 Hopkins University numbers were generously contributed, after their 

 death, to that institution by the National Zoological Park. For 

 ease of comparison the drawings have been made of uniform size, 

 without regard to the real dimensions of the specimens. The hu- 

 meral length, as given to indicate actual size, was taken from the 

 head of the humerus to the lateral condyle. 



No. 2913.— Proceedings U. S. National Museum, Vol. 80, Art. 13. 



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