GALLING. 197 



somewhat technical description is rendered necessary from the very peculiar position 

 this species assumes among birds, and although it may be deemed 'dry reading' it may 

 be permitted in view of the explanation needed why the hoatzin, as it is called, 

 should constitute an order by itself. Not much is known of the economy and habits 

 of this species. It is a native of Guiana and the country watered by the Amazon. It 

 abounds on the low shores of that river, and about the lakes, goes in small flocks of 

 from ten to twenty individuals, and feeds on the leaves of the Arum arboreum, which 

 give to it a very disagreeable odor. Its flight is slow and heavy, and it is not seen on 

 the ground nor on high trees, but remains upon the branches of the arum. The 

 nest is composed of sticks loosely laid together, and placed on low bushes near water. 

 On April 14, 1884, Mr. E. A. Brigham, in a paper read before the Chicago Academy 

 of Sciences, gave an account of a remarkable discovery made by him regarding this 

 curious bird, which would seem to show that, for a period after issuing from the egg., 

 it might be considered as almost belonging to the quadrupeds. The following ex- 

 tract contains the pith of his announcement. " While making embryological studies in 

 the interior of the great island of Marajo, on the small river Anabiju, I discovered 

 the quadruped bird. After examining many specimens of various ages, I found that 

 from what corresponds to about the embryonic state of development of the common 

 fowl at the tenth day of incubation, the fore feet showed their characters unmistak- 

 ably throughout their egg-development, and to a period of several days after hatching 

 the fore feet, toes, and claws held their characters as such, as unmistakably as those 

 parts of the posterior members. Later a progressive modification manifested itself by 

 reducing the digits, exfoliating the claws, and developing these anterior members into 

 those characteristic of a bird. There is, among the higher vertebrate animals so far 

 as I know, no other example of post-natal metamorphosis in such fundamental organs 

 to anything like this extent. The law enunciated by Von Baer that the phyloge- 

 netic development is represented in the ontogenetic has a wide expression here. 

 An important ancestral feature is persistent beyond the egg or parental development. 

 The animal, progressing in its embryonic course, passes into its reptilian ancestral type, 

 and before its evolution has carried it through this, its reptilian phase, it emerges 

 from the egg. Thus from an egg laid by a two-footed, two-winged bird hatches a 

 quadruped animal. For several days after hatching it retains its quadruped charac- 

 acter, then, in the open air and sunlight, one pair of legs evolves into wings. Front 

 legs are purposeless in a bird." A confirmation of these statements is greatly to be 

 desired. 



OKDER XII. GALLING. 



This great division of the class Aves, sometimes designated as Rasores, from the 

 hnbit indulged in by its members of scratching the earth when searching for food, is 

 composed of two sub-orders and four families, viz., TetraonidaB, Phasianida3, Megapodi- 

 das, and Cracidaa, containing among them between three and four hundred species. 

 The sub-orders are called respectively the Alectoropodous Gallinre, those having feet 

 like a fowl, containing the first two families, and the Peristeropodous Gallinre, or 

 those with feet like a pigeon, which includes the last two families. The two sub- 

 orders compose the group known to naturalists as Alectoromorphre. 



The order Gallina? contains within it those species of birds which are most impor- 

 tant and valuable to mankind, affording food to multitudes of people, and which are 



