35 6 



Correspondence. 



[October 



until now I have had no time to further investigate this interesting struc- 

 ture, but will briefly remark here that I found it present, i. e. the dcrmo- 

 tensor fatigii muscle, in all the Acromyodian Passeres that I have thus 

 far examined, and it was entirely absent in an alcoholic specimen of Ty- 

 rannies tyrannus, kindly supplied me by Mr. H. K. Coale, President of the 

 Ridgway Ornithological Club of Chicago. 



I introduce two figures here showing the absence and presence of this 

 muscle on the occasion I examined it. 



It is quite possible that this muscle may exist in other birds. I have 

 nowhere stated that it does not, so far as I can remember. But I will say 





JU^.Z. 





FlG. i. Outer aspect, right arm of Xatithoccphalus xantkocepkalus, showing a dis- 

 section of the muscles of the region in question. 



FlG. 2. The same of Tyrannus tyrannus; slightly enlarged. Both figures drawn by 

 the author from his own dissections, dt. p. dermo-tensor patagii ; //. /., tensor patagii 

 longus ; tp. b., tensor patagii brevis ; b, biceps ; /, triceps ; e. in. r. /., extensor metacarpi 

 radialis longus ; 5. A\, secondary remiges. 



that if it is constant for the Acromyodian Passeres, and absent in the 

 Mesomyodian Passeres, the fact will constitute a taxonomic character of 

 value. If it is subsequently found to exist in both, a complete examina- 

 tion of it in our American birds will be a good thing; I do only insist that 

 I found at least one Kingbird wherein it was entirely absent, and that it 

 was present in a long list of Oscines. 



With these few brief remarks upon the subject I close the case for the 

 present, with the hope that other dissectors with good eyes will look into 

 the matter. But if you illustrate your work, let us, gentlemen, have intel- 

 ligent drawings. 



Very faithfully yours, 



R. W. SlIUFELDT. 



Fort Wingate, N. Mexico. 

 13th Sept., 1887. 



