OSTEOLOGY OF THE YOUNG OF HOATZIN 605 



On the apteria, the down feathers are pretty well distributed 

 over the body and limbs, and are well developed, being more or 

 less abundant, particularly upon the sides of the body and upon 

 the thighs. The free margins of the wings are also abundantly 

 feathered from the thorax to the carpus of wither brachium. 



This is as much as these young specimens show of the ptery- 

 losis of Opisthocomus cristatus ; but it foreshadows what we may 

 reasonably expect to find in the adult bird, which appears, in 

 the main, to have been more or less correctly described by 

 Nitzsch in his great classic on Pterylography. It may be well 

 further to note that C. J. Sundevall ('73) describes a specimen 

 which he casually examined; he came to the conclusion that the 

 vinculum of the foot was absent, and consequently Opisthocomus 

 must have passerine affinities. Garrod ('79), however, soon 

 corrected this, and not only found the vinculum present, but of 

 large size. 



BIBLIOGRAPHY 



Beddard, Frank E. 1889 Contribution to the anatomy of the hoatzin, Opis- 

 thocomus cristatus, with particular reference to the structure of the 

 wing in the young. Ibis, ser. 6, vol. 1. 



1898 The structure and classification of birds. Structure and classi- 

 fication of Opisthocomis cristatus. 



Beebe, W. 1917 Tropical wild life, vol. 1, New York. 



Beebe, C. W. 1909 A contribution to the ecology of the adult hoatzin. Zoo- 

 logica, vol. 1. (Reprinted in Smithsonian Report for 1910.) 



Chubb, C. 1916 The birds of British Guiana, vol. 1. London. 



Cabinis, J. 1870 Eier des Opisthocomus cristatus. J. f. O., Bd. 10, pi. 1, 

 fig. 3. 



Deville, E. 1852 Observations faites en Amerique sur les mo^urs de differ- 

 entes especes I'oiseaux-mouches, suivies de quelques notes anatomi- 

 q'ues et de moeurs sur I'hoatzin, le cauvale, et le savacou. PI. 9. Also, 

 same title, Compt. Rend, de I'Acad. Sci., 34. 

 1852 Rev. et Mag. Zool., ser. 2, vol. 4. 



Garrod, Alfred H. 1879 Notes on points in the anatomy of the hoatzin. 

 P. Z. S., Feb. 4, figs. 1 and 2 and diagram. 



Gadow, Hans 1891 Description of the modification of certain organs of the 

 hoatzin. Zool. J. B. 5. Abth. Syst. and Proc. R. Irish Acad. 2 (3). 



Gervais, Paul 1856 Exped. Amerique du Sud. Zool. Anat. (Castelnau). 



Goeldi, E. A. 1895 Opisthocomus cristatus besitzt in seiner Jugend (und 

 bloss dann) ein Krallenpaar an jedem Fliigel. Orn. Monatsber., 

 Bd. 3. 



1895 Opisthocomus cristatus a cigana hesenha ornithologica. Bol. 

 Mus. Paraense, vol. 1. 



