BIRDS OF NORTH AND MIDDLE AMERICA. 5 



Saurognathous (or segitho-schizognathous) , zygodactylous Cora- 

 ciiformes (Pici) with tongue more or less (usually greatly) extensile, 

 cylindrical, but with tip horny and barbed; rectrices twelve, but the 

 lateral pair rudimentary or greatly reduced in size. 



Vomer split (the lateral halves separated) ; basipterygoid processes 

 absent; maxillo-palatines small, not coalesced; manubrial process of 

 sternum bifurcate ; f emoro-caudal and semitendenosus muscles present, 

 ambiens and accessory f emoro-caudal muscles absent; caeca absent 

 or rudimentary; left carotid artery, only, present; spinal pteryla 

 well-defined on neck, without interscapular fork, but enclosing a 

 dorsal apterium; sides of breast with two distinct pterylse, united at 

 shoulders; oil-gland tufted; outermost (tenth) primary small, and 

 wings otherwise essentially Oscinine. 



In addition to the above-mentioned characters it may be stated 

 that the tongue itself is quite small, flat, and short, acute and horny, 

 usually armed along the edges with recurved hooks. The horns of 

 the hyoid apparatus are generally very long, and curve round the 

 back of the skull, frequently to the base of the bill, playing in a 

 sheath, when the tongue is thrown forward out of the mouth to 

 transfix an insect or withdraw it from a cavity which can not be 

 otherwise penetrated." 



There are twelve rectrices, of which the outer is, however, very 

 small and rudimentary (Ij^ng concealed between the outer and 

 adjacent feathers), so that only ten are usually counted. The tail 

 is nearly even, or cuneate, never forked, the shafts very rigid in the 

 true Woodpeckers (Picinse); soft in Picumninae. The outer primary 

 is generally very short, or spurious, but not wanting. The bill is 

 chisel or wedge shaped, with sharp angles and ridges and usually 

 straight culmen; sometimes the culmen is a little curved, in which 

 case it is smoother or without distinct ridges or grooves. The tarsus 

 is scutellate anteriorly, at least in part, the posterior side with much 

 smaller, usually more or less polygonal, scales in Subfamily Picinae or 

 with a single row of quadrate scutella (in Subfamily Picumninae). 

 The toes are paired (two directed forward and two backward, the 

 outer, or fourth toe, being permanently reversed), or else there is 

 only one posterior toe (the outer), the first toe, or hallux being 

 wanting. The claws are compressed, broad (vertically), strongly 

 curved, very strong, and acute. 



As implied by the vernacular name of the group, the Woodpeckers 

 are preeminently distinguished for their habit of pecking the bark 

 and decayed wood of trees, in their search for grubs and other insects, 

 and for excavating deep cavities in the trunks or branches of trees 

 in which to deposit their eggs. While by no means peculiar to the 



<^ For further details concerning the structure of the tongue, see Stejneger, Stand- 

 ard Natural History, iv, 1885, 424, 425. 



