Order II. PASSERES. 
Tribe IY. Conirostres. 
Family VI. MusoniAGiDiE. 
The second Subfamily, 
OPISTHOCOMINiE, or IToactzins, 
have the Toes lengthened, and the outer toe not capable of being placed posteriorly. 
Opisthocomus Hoffm * 
Bill short, thick, broad at the base, the culmen much curved to the tip, which is abruptly compressed, 
and obtusely hooked over that of the lower mandible, the gonys of which is short, ascending, and 
terminating in a strong angle posteriorly; the nostrils lateral, pierced in the middle of the bill, rounded, 
a nd surrounded by a membrane. Wings long, with the first five quills graduated, and the sixth the 
longest. Tail lengthened, broad, and much rounded at the end. Tarsi robust, shorter than the middle 
toe, and covered with reticulated scales. Toes very long, slender, the lateral toes equal, entirely 
divided at the base, and the outer one not versatile ; the claws long, compressed, and much curved. 
The sides of the head naked. 
This remarkable bird is peculiar to the northern parts of South America. It lives in small flocks on the banks of 
the rivers, and is by no means shy, allowing the hunter to approach very near. If alarmed at the report of a gun, the 
fl ock takes flight, crying cm era, and they all alight close to each other on the same branch a few paces further off. 
Their food consists of the leaves of a tree which the natives call avinga, or those of the Arum arborescens, which causes 
the flesh of these birds to have a strong musky smell, and to be used as a bait for certain fishes. 
O. cristatus (Lath.) PI. enl. 337., Gal. des Ois. t. 193. 
* Hoffmansegg established this in 1811 (Illiger, Prod. Syrt.Mam.et At;.). In 18l6 Vieillot proposed Orthocorys, which in 1825 he 
changed to Sasa, for the same type. 
July, 1845. 
