SEC. m EXTERIOR PARTS OF BIRDS 141 



the flank, sometimes the vent-feathers or under tail-coverts proper ; 

 I refer to it again in connection with these last.) Though these 

 boundaries seem fluctuating and not perfectly satisfactory, a little 

 practice will enable the student to appreciate their proper use in 

 descriptions, and to employ them himself with sufficient accuracy. 

 The adjectival terms are respectively pedffral, abdominal, and lateral. 

 The anterior continuation of the trunk, or the 



Neck (Lat. collum) is likewise subdivided into regions. Its 

 lateral aspects, except in those birds that have lateral neck-tracts 

 of feathers, are formed by the meeting over its sides of the feathers 

 that grow on the dorsal and ventral pterylse, the skin being usually 

 not planted with feathers. Partly on this account, perhaps, a dis- 

 tinctively named region is not often expressed; we say simply 

 "sides of the neck," or "neck laterally" (paraitchenia ; Fig. 25, 9). 

 The neck behind, or the dorsal (upper) aspect, is divided into two 

 portions : a lower, the " hind neck " proper, or " scruff of the neck " 

 (Lat. cervix ; Fig. 25, 8), next to the back; and an upper, or "nape 

 of the neck" (Lat. nucha; Fig. 25, 7), adjoining the hind head. 

 These are otherwise respectively known as the cervical and nuchal 

 region; and, in speaking of both together, we usually say "the 

 neck behind." , The front of the neck has been needlessly sub- 

 divided, and these subregions vary with almost every writer. It 

 sufiices to call it throat (Lat. gula, Fig. 25, 37, or jugulum, 34) ; 

 remembering that the jugular portion is lowermost, vanishing in 

 breast, and the gular uppermost, running into chin along the under 

 surface of the head. Guttur is a term sometimes used to include 

 gula and jugulum together : it is simply equivalent to " throat," as 

 just defined ; the adjective is guttural. Though generally covered 

 with feathers, the neck, unlike the trunk, is frequently partly naked. 

 When naked behind, it is usually cervix that is bare, as so charac- 

 teristically occurs in herons, from interruption of the forward 

 extension of the pteryla spinalis. Nucha is seldom if ever naked, 

 except as an extension of general bald-headedness. Gula is 

 similarly naked from above downwards, as conspicuously illustrated 

 in the order Steganopodes, comprising the pelicans, cormorants, etc., 

 which have a bare gular pouch ; and as seen in many vultures, 

 whose baldness extends over nucha and gula, and even all around 

 the neck, as in the condor, whose nakedness ends with so singular 

 a collar of close-set, downy feathers. The lower throat or jugulum 

 becomes naked in a few birds, in which a distended crop or craw 

 protrudes, pushing apart feathers of two branches of the pteryla 

 centralis as these ascend the neck. The rule is, that the neck is 

 not the seat of enlarged or otherwise highly developed feathers, 

 which might restrict the requisite freedom of its motion ; but there 

 are some signal exceptions, among which may be instanced the 



