282 ZOOLOGICAL GARDENS. 



upwards ol' a hundred, and varying greatly in the details 

 of their habits, seem to require and to be capable of 

 still farther subdivision; and M. Cuvier has set an 

 example in this respect, which has since been generally 

 follow^ed. For his primary divisions he employs the 

 structure of the hinder toe, which in one set is perfectly 

 simple, while in the other it is bordered by a web. In 

 the former the head is generally smaller, the feet less 

 expanded, the neck of greater length, the bill more 

 equal, the wings longer, and the body less plump. 

 They walk with greater facility ; feed on water-plants 

 and their seeds, as well as on fishes, reptiles, and 

 insects ; prefer fresh water ; possess great powers of 

 flight; and seldom dive unless pursued. The Domestic 

 Duck with the species most nearly i-elated to it, includ- 

 ing the one figured at the head of the present article, 

 make part of this division, in which they form a distinct 

 group, characterized by their well-proportioned bill, 

 without protuberance ; their rounded nostrils ; and the 

 raised position or altered form of their outer tail-coverts. 

 The American Summer Duck, one of the most beau- 

 tiful birds of its family, is considerably smaller than the 

 domestic species, its total length being about nineteen 

 inches, and the expanse of its wing less than two feet 

 and a half. In the male, the upper part of the head 

 is of a deep metallic green, with the feathers of the 

 dependent crest terminating in a rich violet. A line of 

 pure white passes in an elegant curve from the base 

 of the upper mandible above the eye, and a second 

 extends beneath and parallel to the first from imme- 

 diately behind the eye. The cheeks and sides of the 

 neck at its upper part are violet ; and the entire front 

 of the latter, with a collar round its lower part, and 

 two processes like the horns of a crescent bounding 

 the cheeks behind, white. The breast is deep brown, 



