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DK. E. W. SHUfELDT's MORPHOLOGICAL 



third ; at its origin its fibres spread out fan-fashion, their terminal 

 ends meeting those of the muscle of the opposite side in the 

 median line. Here it is quite adherent to the skin, but its fibres 

 rapidly converge as they pass in the direction of the shoulder-joint, 

 ojjposite which region they gradually free themselves from the si<in 

 to form a small fusiform muscle, which, ending in a delicate tendon, 

 runs along within the free marginal fold of the patagium of the 

 wing, in common with the tendon of the tensor patagii longus, to 

 blend with it just before reaching the carpal joint. 



I proj^ose to call this muscle the dermo-tensor patagii, it being 

 partially connected with the integumentary system of muscles in 

 the birds in which 1 have thus far found it. 



Searching for it in all the other American Swallows, I find it 

 to be about equally well developed in every species, and absent in 

 none of theni. 



This muscle surely does not correspond with the " bicipital slip 

 of the patagium," as described by Garrod, and dwelt upon as the 

 tensor jpatagii accessorius by Professor T. Jefiery Parker in his 

 ' Zootomy ' (1884, p. 251) as occurring in the Common Pigeon, 

 for it makes no connection whatever with the biceps muscle. 



Being desirous at this point of determiuiug its presence or ab- 

 sence in a few other groups of bitds, I stepped aside for the 

 moment, and first examined a number of Passerine types, including 

 very diverse forms, — it was present in all of them. Next, with 

 the Caprimulgi, Trochili, and Cypstli, I found it completely ab- 

 sent, as it was also in a specimen of Tyrannus tyrannus, kindly 

 sent me by Mr. II. K. Coale of Chicago, from which 1 am led to 

 inler that it does not occur in the mesomyodian Passeres. 

 Further than this I did not pursue the subject, but left it for 

 subsequent investigation and the reseat ches of others interested 

 in such matters *. 



Of the Pectoral Muscles. 

 Every species of American Swallow has been dissected by 

 me to ascertain the character and number of these important 



* Further opportunities for examining the literature of this subject now 

 enable me to state tli at the muscle here die^cvihQdi \^ the ^' pars propatagialis 

 musculi cucullaris " of Fiirbringer and Gadow ; and it has been carei'ully consi- 

 dered by me in an extensive work upon the muscles of birds now in the hands of 

 the Smithsonian Institution for publication. — E. W. S. 



