PASSERINE BIRDS OF CEYLON. 25 



as the deep plantar tendons, vary in their disposition. They 

 are said to be Passerine when the one tendon serves the three 

 front toes and the other the hind toe, both tendons being 

 wholly discomieeted in such a manner that the hind toe is 

 mobile and worked independently of the other three. All 

 the Passer es are also characterized by possessing an arrange- 

 ment of the bones of the palate known as " segithognathous." 

 The combination of Passerine deep plantar tendons with the 

 above-mentioned form of palate will always serve to distin- 

 guish the Passeres from any other order. I do not propose, 

 however, to go further into these structural characters, as it is 

 not a difficult matter to diagnose all Ceylon forms of the order 

 by outward marks, as follows. 



They are all birds of medium or small size ; with the single 

 exception of the crow family, they never run larger in the 

 body than a Thrush or Mynah, and are frequently smaller. 

 The young when hatched are in a helpless and almost naked 

 condition, being clothed at first merely with a few isolated 

 patches of down. The bill is never furnished at the base with 

 a cere, or membrane of soft skin. The legs are feathered 

 down to, but no further than, the tarsal joint. Lastly, the 

 outward structure of the feet is typically constant. The first, 

 or hind toe, also known as the hallux, i^ always present, and 

 is movable independently of the three front toes, while the 

 front toes are separated from each other down to their bases. 

 Compare, for instance, a crow — a Passerine bird — with an 

 Indian Roller, often erroneously called a Blue Jay. Both 

 birds are of the same size and build, but in the Roller the 

 middle front toe is united to the outer toe at the extreme base, 

 and to the inner toe for the length of the first joint. Again, 

 in certain other orders, such as the Cuckoos, the feet are 

 " zygodactylic," i.e., two toes only are turned to the front, 

 while the first and fourth toes are directed backwards. 



The Passeres are by far the largest order of birds, comprising 

 at least half of all the living species. They are also generally 

 acknowledged to be the most specialized and most highly 

 organized order. In other words, at the present general stage 

 of evolution, they are the dominant ornithological order, 

 and, as Darwin has pointed out, dominant groups show the 



4 6(17)21 



