8 BIRD GALLERY. 



tlic palatine, but forming a close union citliev hy fusion or l)y over- 

 lapping suture uitli the base of tlic vomer. 



'Die majority of the members of this groiip liavc become flightless, 

 a fact which has brought about many modifications of the skeleton 

 and feathers. The Tinamous alone have retained tlie power oi: 

 flight. 



The Ratitaj are divisible into seven Orders, probably derived from 

 three distinct stocks. Each Order can be readily defined, and presents 

 one or more points which indicate extreme specialization. 



On account of tlie structure of the palate, the form of the bones ol 

 the pelvis, and other anatomical characters, the members of this section 

 may be regarded as tlie most primitive of living birds. 



The seven Orders of the Ratit;e arc the following : — 



1. Struthiones One genus, Stnit/ilo. 



2. Rhese One genus, li/iea. 



3. Dinornithes ") ^, .,, . . 



, ^^ .,, (• r^umcrous genera. TAtinct forms. 



I. yiiipyornithes . . . .} " 



ij. Casuarii Two genera, Cufiniiniin and DronucuK. 



<). Apteryges One living genus, Ajjicri/x, and two 



extinct genera. 



7. Crypturi Numerous genera. 



The characters l)y which the Orders are distinguished are fully 

 explained in tlie table-ease in the first bay. 



[Case 1 and 

 Centre Case Order I. STRUTHIONIFORMES. OsTRun-TRiBE. 



in Ray.] 



Though closely allied to the Rhcas, which they resemble in general 

 appearance, the members of this order may be at once distinguished 

 from all others by possessing only two toes. Of these the one corre- 

 sponding to the middle of the three anterior toes in ordinary birds (the 

 third of the complete set) is much the largest and supports the greater 

 part of the weight. It bears a stout pointed nail. The smaller outer 

 (or fourth) toe often wants the nail. The whole of the head and neck 

 as well as the legs are bare, or only covered with short down. Tlie body- 

 feathers are single, having no aftershaft, and the featliers of the wings 

 and tail (corresponding to the ' remiges ' and 'rectrices' of ordinary 

 birds) arc of considerable size, but soft and plumose. 



Family Struthioxiu.i:. OsTuicnEs. 



The Ostriches, the largest of living birds, are represented by the 

 single genus Slfid/iio, which contains at least four living species in- 



