STTJDIES OF THE MACROCKIRES. 



373 



of the plumage is quite different ; aud the position of the " humeral 

 tract " in the pterylosis is different, being across the middle of 

 the humerus in Swifts, and OYerlyiug the head of the bone in 

 Humming-birds. 2. The mode of insertion ot" the patagial muscles, 

 as well as Wieform and character of these muscles themselves, is 

 altogether different in the two groups. 3. The method of inser- 

 tion of the pectoral muscles is essentially different. 4. Through- 

 out the entire skeleton of this limb, the individual bones in Swifts 

 and Humming-birds differ widely in characters of the very highest 

 import, both morphologically and in the position, absence, and 

 presence of parts. 



All this being so, I am firmly convinced that were the minor 

 details in structure in these two wings carefully worked out 

 under the lens of a good microscope, they too, of necessity, would 

 also be found to be at variance. Indeed, in making my own 

 dissections of the Trochili under a 2-iuch objective I saw quite 

 enough to fully confirm this suspicion. 



Finally, I must say, as 1 have already remarked in a previous 

 paragraph, that heretofore too much stress has been laid upon 

 the fact that both Cypseli and Trochili possess short humeri; 

 and, further, to my mind, shortness, per se, dot s not constitute a 

 valid character, for if it did, some very remarkable forms would 

 surely be grouped together ! My painstaking labours upon the 

 wing-structure of Swifts and Humming-birds convince me fully 

 that, in so far as this part of their organization is concerned, 

 there is little or no affinity at all. 



Notes on the Anatomy of the Pelvic Limh in certain 

 Cypseli and Trochili. 



Having shown how innately different the wing-structure in 

 Swifts and Humming-birds really is, let us now take a look at 

 their pelvic limbs. 



It will not be necessary to pass the external characters of these 

 parts in review, as they are already well known ; it will be suf- 

 ficient to remark that the pelvic limb of such a bird as Micropus 

 differs from the pelvic limb of a Trochilus in all its more essential 

 external characters. 



My investigations tend to confirm the statement of Pro- 

 fessor Garrod, that Humming-birds and tlie American Swifts 

 Chcetura pelagica and Micropus lack the accessory femoro- 



