1896.] ANATOMY OF THE HOATZIN. 619 
laboratory at’ the Gardens in the course of my investigations into 
the anatomy of birds. A number of important memoirs have 
appeared upon the Hoatzin, but, in the present condition of our 
knowledge of the relations among the groups of birds, additional 
details concerning the structure of a type so aberrant may prove 
useful. 
Alimentary Canal. 
The extraordinary crop and the general characters of the gizzard 
and intestines have been sufficiently described by L’Herminier ' 
and Gadow’*. Following the method which I have described in a 
former paper *, I dissected out the coils of the intestine and the 
Fig. 1. 
Intestinal convolutions of Opisthocomus cristatus. 
x, bridging-vessel divided ; y.m., mesentery of the yolk-sac vestige. 
great veins in a well-grown chick and in three adults. As shown 
in figure 1, the duodenal loop is unusually short and wide, and is 
much less specialized than in most other birds I have examined, 
1 “Recherches anatomiques sur quelques genres d’oiseaux rares ou peu 
connus,” Ann. Sci. Nat. sér. 2, Zoologie, viii. Paris, 1837. 
2 “On the Taxonomic Value of the Intestinal Conyolutions in Birds,” 
P. Z. 8. 1889, p. 303. 
* “Qn the Intestinal Tracts of Birds,” P. Z. S. 1896, p. 136. 
40* 
