69 



PICINiE. 



WOODPECKERS AND ALLIED SPECIES. 



Like the Psittacinae, the Picinse form a well-defined group, 

 of which the aflanities are not obvious. Their more essential 

 characters are to be found in their straight, tapering, angular 

 bill, which is wedge-shaped at the end, and constructed for the 

 purpose of splitting or perforating bark and decayed wood ; and 

 their graduated decurved tail, of which the feathers have very 

 strong, elastic shafts, with attenuated webs ; together with 

 their short, strong, zygodactylous feet, and stout, compressed, 

 curved acute claws. The peculiarities of their tongue and di- 

 gestive organs have already been described. The skeleton pre- 

 sents several remarkable peculiarities as compared with that of 

 a Jay or other bird of that family. 



The skull is of moderate size, roundish-oblong, the orbits 

 with very prominent margins, which are nearly complete, and 

 thus approach to those of the Psittacinae. A double groove for 

 the horns of the hyoid bone is apparent in the median part of 

 the skull, and there is a deep and broad cavity on the forehead, 

 between the anterior parts of the orbits. The jaws are straight 

 and rather long, the lower very deep at the base. There are 

 twelve cervical vertebrae, eight dorsal, twelve lumbar and sacral, 

 and eight caudal. The ribs, eight in number, are stout, the 

 two anterior incomplete. Of the caudal vertebrae the last or 

 eighth is extremely large, presenting a broad plate beneath ; 

 the seventh is anchylosed with it ; the eighth has a deep notch 

 behind at its lower part, into which is received the very strong 

 inferior spinous process of the sixth, when the tail is depressed. 

 The downward curve of the tail is performed chiefly at the 

 joints between the fifth and sixth, and the sixth and seventh. 

 At the latter the tail may be curved upwards, so as to lie flat 



