THE CLASSIFICATION OF BIRDS 49 



ptery golds and palatines behind. The backward position of 

 the basipterygoid processes, which are situated on the basi- 

 sphenoid rather than on its rostrum, is another eminently Struthi- 

 onine character, though it reappears in the Turnicidcc. Precisely 

 the same remarks apply to the curious fact that the male of the 

 Tinamous incubates the egg. 



GALLTFORMES. 



It is curious how many characters the Passeri formes have in 

 common with some of the Galliformes. That they both belong to 

 the Passeromorphae implies that every species in both Orders has 

 normal plantars and is quincubital. The Passeriformes feed their 

 young in the nest for many days, and it is said that Opistliocomus, 

 one of the Galliformes, and Eurypyya, one of the Turniciformes, 

 do the same. The Passeriformes have a very simple pterylosis, 

 the spinal feather-tract is well defined on the neck and is not 

 forked on the upper back; a similar pterylosis is found in the 

 Crypturi amongst the Turniciformes, and in many of the Phasi- 

 anidee amongst the Galliformes. All the Passeres (except the 

 Eurylcemidce) are without any vinculum to connect the two deep 

 plantar tendons, and the same peculiarity is found in the Upupaa 

 amongst the Cuculiformes. 



It is not known that any of the Galliformes have lost the 

 ambiens muscle. 



The Galliformes may be arranged in two suborders, the 

 Psophiae and the Galli, which differ from each other in various 

 ways. In the first place, they differ in -their pterylosis, the 

 Psophige having the down of the adult more or less sparingly 

 distributed over the bare spaces as well as over the f eather- tracts, . 

 whilst in the Galli it is confined to the latter. The Galli resemble 

 the Anatidce in having the basipterygoid processes placed as far 

 forward as possible ; in the Psophige they are absent altogether. 

 The Galli resemble the Upupidce, the Meropidce, and the Bucero- 

 tidce in having the anterior and posterior episternal processes 

 fused together to form a bridge over the coracoids, a peculiarity 

 not found in any other birds. 



