46 Zoologica: N. Y. Zoological Society. [I; 2 



being flabby and glandular, are thick and muscular. This in- 

 crease in the size of an organ situated far forward in the body 

 has resulted in a reduction of the front part of the keel of the 

 sternum, a condition unique among birds. In reducing the area 

 of attachment for the pectoral muscles, this change has radically 

 affected the power of flight. 



In spite of this specialization, there is no doubt that the 

 Hoatzin is an extremely ancient and isolated type, and it has 

 very properly been set aside in a separate Order by itself — 

 Opisthocomiformes (43). Combining, as it does, the characters 

 of several Orders, it is impossible to indicate its correct position 

 in a linear classification. In such artificial, two-plane, genealog- 

 ical trees, it has been variously placed between the game birds 

 and the rails; between the pigeons and the rails; while it has 

 certain affinities with the plantain-eaters, and the vestigial claw 

 on the third digit links it with the primitive Archaeopteryx. 



Another claim to a primitive condition is found in the quad- 

 rupedal habits of the young. These, by means of unusually de- 

 veloped fore limb and fingers, and external claws on the first and 

 second fingers, are able to climb actively about the bushes. They 

 also swim and dive well. 



Part II — History. 



More than two hundred and fifty years ago Hernandez, in 

 his Nova Plantarum, Animalium et Mineralium Mexicanorum 

 Historia (22) , makes the first authentic mention of the Hoatzin, 

 writing in Latin as follows : 



"The Hoatzin, — a bird uttering a curious note, sounding like 

 its name. 



"This is a bird of about the size of an Indian fowl. Its beak 

 is curved; its breast shades from white to buff; its wings and 

 tail are spotted with white at intervals of a thumb's length ; the 

 back of the upper part of its neck is yellow, shading into blackish 

 on both sides and sometimes extending as far as the beak and 

 eyes ; the claws are black and the legs blackish. The bird bears 

 a sturdy crest of feathers, varying from white to yellowish, the 

 back of each feather, however, being black. The bird subsists 

 upon snakes. It has a powerful voice which resembles a howl- 

 ing or wailing sound. It is heard in the autumn and is held in- 

 auspicious by the natives. . 



"The bones of this bird relieve the pain of wounds in any 

 part of the human body ; the odor of the plumage restores hope to 

 those who, from disease, are steadily wasting away. The ashes 



