RATITAE. 



457 



lated with the basisphenoidal rostrum, being usually separated from it, 

 and supported, by the broad, cleft, hinder end of the vomer (dromaeo- 

 gnathous). (4) Strong basipterygoid processes, arising from the body of 

 the basisphenoid and not from the rostrum, articulate with facets which 

 are situated nearer the posterior than the anterior ends of the inner edges 

 of the pterygoid bones. (5) The upper articular head of the quadrate 

 bone is not divided into two distinct facets. (6) The barbs of the feathers 

 are disconnected, the barbules being without hooks. (7) There is no 

 sjTinx. (8) The wings are reduced in size, there is no pygostyle and no 

 oil gland, and the uncinate processes of the ribs are small or absent. 



The plumage covers the whole body with tolerable vmiformity, except 

 that there are naked places on the head, the neck, the extremities, and 

 the abdomen. It dees not present any regular arrangement of pterylae. 

 The down is much re- 

 duced, but the contour 

 feathers have a down- 

 like appearance on , 

 account of their flexible 

 shaft and lax ^'ane, or 

 they may be stiff and 

 hairlike, with setiform 

 barbs, or sometimes, 

 as in the wings of the 

 cassowary, they are 

 spinelike. The rham- 

 photheca is composed 

 of several pieces. There 

 is a large penis and the 

 young are praecoces. 

 Fossil remains are not 

 numerous ; the oldest 

 are those of Struthio 

 from the Upper Mio- 

 cene of the Siwalik 

 Hills, etc. The other 

 genera do not for 

 the most part go back 

 beyond the Pleisto- 

 cene. 



Fam. 1. Struthion- 

 idae. Ostriches. With 

 naked head and neck, pubic symphysis, and long, naked legs. 



Fig. 250. — Aj'teryx o'i'eni {fron\ Clans 



The 



maxillopalatines articulate with facets on the sides of the vomer ; the 

 vomer is short and does not articulate either with palatine or pterygoid. 

 The pes has only two digits, viz. Nos. 3 and 4. The feathers are with- 

 out an aftershaft. They inhabit the plains and deserts of Africa and 

 Arabia. They live in companies and are polygamous. The cock under- 

 takes the greater part of incubation. Struthio camelus L. 



Fam. 2. Rheidae. With partially feathered head and neck, with 

 three-toed feet, and with ischiadic symphysis. The palate is di'omaeo- 

 gnathous. The feathers have no aftershaft. South America. Rhea 

 umericana Lam., the rhea. 



Fam 3. Casuariidae. With high almost compressed beak, and usually 



