330 DR. R. w. shufeldt's moephological 



are to be found the two usual tuberosities for articulation with 

 tlie bones of tlie antibracbium. 



In neither of the Trogon skeletons at hand do I find any 

 sesamoid bones present at the elbow-joint ; but it is just possible 

 that these birds may possess them, and that in the prese^^t 

 instance they have been lost in the preparation of the skeleton ; 

 I am inclined to believe, however, from the general appearance 

 of the dried ligaments and other structures that have been 

 retained in one specimen, that the Trogons do not have these 

 ossicles at the elbow-joint. 



Turning to the bones of the forearm, we observe that the shaft 

 of the 7'adius is very slender and nearly straight. Its extre- 

 mities are comparatively but slightly expanded, and on the 

 w^hole this bone is not so powerfully developed as we find it in 

 many birds of the same size. The interosseous space between it 

 and the ulna is ample, but is largely due to the curvature in the 

 shaft of the latter bone. The ulna has the usual form as we 

 find it in some of the Passeres. Its olecranon process, however, 

 is not conspicuous, while the shaft is smooth, subcylindrical, and 

 devoid of the row of papillae for the insertion of the quill-butts 

 of the secondaries of the wing, so prominent in some birds, as, 

 for instance, many of the Picidcd. 



Badial and ulnar ossicles compose the carj^al joint, and make 

 the usual articulations with the surrounding bones. I am unable 

 to discover any sesamoids about this joint, and am of opinion 

 that none exist. 



Extending our observations to the hand, we may note the 

 peculiar form of its main bone, the carpo-metacarpal. This 

 peculiarity does not consist in any radical change of its form as 

 it is found to be in most birds, but of the unusual width it as- 

 sumes at its distal end, in the antero-posterior direction (PI. XIX. 

 fig. 13). The increase of surface thus gained is for the accom- 

 modation of the articular facet for the single and terminal 

 phalanx of mid-metacarpal digit, here disproportionately large 

 as compared with the bones of the other two phalanges. 



PoUex phalanx is small, slender, and trihedral in form ; it is 

 not provided with a claw at its distal extremity. 



A very similar joint is the distal phalanx of index digit, and 

 this, too, is without a terminal claw. 



The proximal bone of this finger has the general form it as- 

 sumes among birds, but in the present instance the expanded 



