218 VEBTEBRATA. 



to the back of the head, forming a bow which can be lengthened 

 or shortened by accompanying muscles. 



The palatal structure is " at a most simple and Lacertian 

 stage" (Parker). The voraers are delicate rod-like bones which, 

 in some cases, remain permanently separate. The qu;idvate bone 

 is very short. The sternum has two notches on each side pos- 

 teriorly, and a forked manubrial process. There is only one 

 carotid. The tarsi are covered with short imbricated scales 

 anteriorly. In Sasia and Apternus the inner posterior toe is 

 wanting. 



The Pici are shy untamable birds, flying from man, living in 

 woods, and nesting in holes of trees ; the males share the duty of 

 incubation. They live on insects and worms, or on fruit ; some 

 of the North- American species of Melanerpes are said to enter 

 dovecots for the purpose of sucking the eggs of pigeons. They 

 creep, rather than climb, on the trunks and branches of trees. 

 Picumnidae are exceptional; their tail-feathers are broad and 

 rounded at the tip, and they do not appear to climb. 



Sundevall was the first (but only for a time) to separate these 

 birds as an order, in which he is followed by Carus and Huxley. 

 To it belongs the green woodpecker (Gecinus viridis), great spotted 

 woodpecker (Pious major], black woodpecker (I)ryocopus martins], 

 and the wryneck (Yunx torquiUa). 



There are 350 species in G. E. Gray's ' List ;' but none are 

 found in Madagascar or in Australia. 



Picumnidcs. Ohrysoptilus. Hemilophus. 



Picumnus. Chrysonotus=Tiga. Dryocopus. 



Sasia. Gecinus. Campophilus. 



Celeus. Picus. 



Picida (Wood- Meiglyptes. 



peckers). Colaptes. Twigida. 



Apternus = Picoides. Geocolaptes. Yunx (Wryneck). 



Melanerpes. 



Order II. VOLITOEES. 



FISSIROSTRES. PICARLE. STRISORES. COCCYGOMORPH^B. 



Bill various, with mostly a wide gape ; no cere. Legs small 

 and weak ; a back toe, outer toe sometimes reversible. Wings 

 strong. 



In this order the bill is often remarkable for length or breadth, 

 or both. The feet are mostly small, with little grasping power. 



