VERTEBRATA: AVES. 



619 



CHAPTER LXVL 



SUB-CLASS C A RIN AT & Continued. 

 SCANSORES, INSESSORES, AND RAPTORES. 



ORDER IV. SCANSORES. The order of the Scansorial or Climb- 

 ing birds is easily and very shortly defined, having no other 

 distinctive and exclusive peculiarity except the fact that the 

 feet are provided with four toes, of which two are turned back- 

 wards and two forwards. Of the two toes which are directed 

 backivards, one is the hallux or proper hind-toe, and the other is 

 the outermost of the normal three anterior toes. This arrange- 

 ment of the toes (fig. 342, B) enables the Scansores to climb 



Fig. 342. A, Skull of a Parrot (Psittacus erythacus). B, Foot of the same : a Hallux ; 

 b Index ; c Middle toe ; d Outer or ring toe. (After Blanchard.) 



with unusual facility. Their powers of flight, on the other 

 hand, are generally only moderate and below the average. 

 Their food consists of insects or fruit. Their nests are usually 

 made in the hollows of old trees, but some of them have the 

 remarkable peculiarity that they build no nests of their own, 

 but deposit their eggs in the nests of other birds. They are 

 all monogamous. 



The order Scansores, as above defined, must be looked upon 

 as a. purely artificial assemblage, comprising birds which pos- 

 sess in common the peculiarity of a scansorial foot, but which 

 otherwise are widely different The order is only retained 

 here because it can hardly be dispensed with otherwise than 

 by raising the three principal groups contained in it to the rank 

 of separate orders (viz., the Cuculidce, Picidce, and Psittaridce). 



