914 DR. R. W. SHUFELDT ON THE OSTEOLOGY OF THE [DeC. 1, 



and, as we know, it is pretty well represented in nearly all parts of 

 the world. Structurally, on the one hand, their relationship to the 

 Owls is very close, through Podargus and Steatornis. Opportunity 

 has not been afforded nie to pick up the other end of the thread, 

 but I am very confident that their affinity with the Swifts is anything 

 but a near one. 



V/ith the exception of a few minor points in their organization, the 

 Swifts are essentially modified Swallows, and, as the family Cypse- 

 lidEe, they belong, in the order Passeres, next to that group. The 

 fact, that in common with Humming-birds, so far as we know the 

 structure of these latter, they have a short humerus and an entire, 

 unuotched xiphoidal extremity to the sternum, is no more reason 

 that the two groups should be classed together, than Talpa and 

 Ornithorhynchus should be for like resemblances. Such similarities 

 are due to physiological adaptation of structure, referable in the 

 present instance to the pecular flight of these birds, and the conse- 

 quent requirements of the muscles involved in it. Moreover, our 

 investigations above have shown really how very different these 

 parts are when they come to be carefully compared. So far as the 

 skeleton goes, and it is usually supported by associated parts, the 

 entire summation of the truly fundamental characters of the genus 

 Trochilus are at great variance with the corresponding ones in the 

 skeleton of Ci/psehis, and militate against the propriety of retaining 

 .such forms closely associated together in the same group. 



The anatomy of the Humming-birds is not as yet sufficiently well 

 known for us to exactly define their position in the system ; but if we 

 may be permitted to judge from the skeleton oi TrocMlvs, there is no 

 reasonable doubt that the extraordinary characters it presents fully 

 entitle these birds to a group by themselves, as an order Trochili. 

 Morphologically (and morphology is really the only guide, when 

 properly interpreted, that we possess, to natuial taxonomy) such a 

 group, I think it will be found, can be fully as well characterized as 

 the Psittaci are, and rested upon fully as firm a foundation, and 

 equally as well circumscribed. It would contain upwards of 500 

 species, which is very considerably larger than the order containing 

 the Parrots. 



At the present time I am not prepared to say much about the 

 affinities of this group, as 1 should first like to examine a number of 

 Old- World forms before advancing an opinion. 



Ko little significance, however, attaches to the facts brought to 

 light through the dissections of the Troyonidce by tiie late and 

 lamented Forbes (P. Z. S. 1881, p. 836), showing the construction 

 of the palate in these birds. It will be seen from the figure this 

 author presents of Pharomacrus mocinno in the work referred to, 

 that the maxillo-palutines in this Trogou are well separated in the 

 median line, that the vomer is long, free, and slender, and that the 

 palatines nowhere come in contact with each other, and are far 

 apart behind. All this agrees with Trochilus, and I only regret that 

 I have not at hand a few skeletons of different Trogons to further 

 compare these birds with the Humming-birds. 



