STUDIES OF THE MACROCHIRES. 



333 



articulation with the shaft o£ the tarso-metatarsus at its most 

 usual site. 



Measuring the lengths of the several bones of this pelvic limb, 

 as we did in the case of the pectoral one, we find that the femur 

 is 2*3, the fibula 2-1, the tibia 3"3, and the tarso-metatarsus 1'6 

 centimetres long. 



Without measuring the several lengths of the joints of the 

 pedal digits of a Trogon, I am enabled to say that they are quite 

 as harmoniously proportioned as are the corresponding phalanges 

 of the average foot of any Passerine bird that I have ever 

 examined. 



This completes my description of the skeleton of T. mexicanus, 

 and, as observed, it will apply with almost equal exactness to the 

 skeleton of T. puella. In proceeding with my account I have 

 been careful, I believe, in every instance to point out any con- 

 stant character that seems to distinguish them ; and no doubt 

 my description will practically answer for other nearly related 

 species of this handsome group of birds. 



It seems scarcely necessary to tabulate the salient features of 

 the osteology of this Trogon here, as my brief account presents 

 but little more than an enumeration of the essential charac- 

 teristics. It will therefore be omitted, in the belief that the 

 several figures illustrating my text and the description will be 

 amply sufficient even for convenience of reference. 



Comparing these osteological characters of Trogon with the 

 corresponding ones of such a Humming-bird as T. Alexandria as I 

 presented the latter in my former memoir, P. Z. S. 1885, it will 

 at once become evident to us that, so far as the skeletology of 

 the two forms is concerned, there is absolutely little or nothing 

 that mutually characterizes them. 



So much for the comparative osteology of Humming-birds and 

 Trogons, but this will not exactly apply to some other grou})s of 

 birds, such, for example, as the Cuckoos and Nightjars ; and I 

 will now proceed to draw a few comparisons among some of 

 them. 



I regret to say that the only (^uckoo-like bird I have at hand 

 is Geococcyx californianus, and, as stated above, I have already 

 published an account of its osteology in the ' Journal of Ana- 

 tomy.' I did have, not long ago, a fairly good skeleton of 

 the Yellow-billed Cuckoo {Coccyzus americanus) ; but Prof. 

 Parker was at that time in search of all the Cuculine birds 



26* 



