EXTERNAL PARTS OF BIRDS. — TOPOGRAPHY. 103 



term "temporal region" or "temple" is not often used in ornithology, not being well distin- 

 guished from a post-orbital space between eye and ear, and having nothing special about it. 

 At lowermost back corner of side of head, generally just behind and below ear, may be seen or 

 felt a hard protuberance; this is the sharpest corner-stone of the head, being the place where 

 the lower jaw hinges upon the skuU. This is called "angle of jaw"; it is a good landmark, 

 which must by no means be confused with "angle of mouth," where horny parts of the beak 

 come together. The lore (Lat. lorum, a strap, or bridle ; hence, place where the cheek-strap 

 passes ; fig. 25, 2) includes pretty much all the space between eye and side of base of upper 

 mandible; a considerable uart of it is simply ante-orbital. Thus we say of a Hawk, "lores 

 bristly " ; and examination of a bird of that kind will show how large a space is covered by the 

 term. Lore, however, should properly I)e restricted to a narrow line between eye and bill in 

 direction of nostrils. It is excellently shown in Herons and Grebes, where " naked h)res" is a 

 distinctive character. The lore is frequently the seat of specially modified or specially colored 

 feathers. The rest of side of head, including space between angle of jaw and bill, has the name 

 of cheeTc (Lat. gena; fig. 25, 35). It is bounded above by loral, infra-orbital, and auricular re- 

 gions; below, by a line along lower edge of bony prong of under mandible. It is cleft in front 

 for a varying distance by backward extension of gape of mouth ; above this gape is more prop- 

 erly gena, or malar region (Lat. mala, upper jaw) in strictness; below it is jaiv {maxilla), or 

 rather " side of jaw." The lower edge of jaw definitely separates side of head from " under 

 surface " of head, which is a space bounded behind by an imaginary line drawn straight across 

 from one angle of jaw to the other, and running forward to a point between forks of under man- 

 dible. As already hinted, " throat" (gula ; fig. 25, 37) extends upward and forward into this 

 space without obvious dividing line; it runs into chin (Lat. mentuni; fig. 25, 38), which is the 

 (varying in extent) anterior part of under surface of head. Anteriorly, mentum may be marked 

 off, opposite the point where feathers end on side of lower jaw, from a feathery space (when 

 any) between branches of upper mandible itself; this space is called interramal (Lat. inter, be- 

 tween; ramus, fork). 



The head is often striped lengthwise with different colors, apt to take definite position ; 

 these lines have received special names. Median vertical line is one along middle of pileum, 

 from base of bill to nucha ; lateral vertical lines bound it on either side. Superciliary line has 

 already been noticed ; below it runs the lateral line ; that part of it before eye, is loral or ante- 

 orbital; behind eye, post-orbital; when these are continuous through eye, they form a trans- 

 ocular (Lat. trans, across; oculus, eye) line; below this is malar line, or cheek-stripe (Lat. 

 frenum, a bridle); below this, on under jaw, maxillary or submaxillary line; in the middle 

 below, mental or gular lines. 



No other part of the body has so variable a ptilosis as the head. In most birds it is wholly 

 and densely feathered ; but it ranges from this condition to one wholly naked ; though such 

 nakedness means only absence of perfect contour feathers, for most birds with unfeathered heads 

 have a hair-like growth of filoplumes. Our examples of naked-headed birds are Turkeys, Vul- 

 tures, Cranes, and some of Ibises. Associated with more or less complete baldness, is frequent 

 presence of various fleshy outgrowths, as combs, tvattles, caruncles (warty excrescences), lobes, 

 and flaps of all sorts, even to enumerate which would exceed our limits. The parts of the barn- 

 yard cock exemplify the whole; among North American birds they are very rare, being almost 

 confined to Turkeys. Sometimes horny plates take the place of feathers on part of the head ; 

 as the frontal shields of Coots and Gallinules. A common form of head-nakedness marks one 

 whole order of birds, Steganopodes, which have mentum and more or less of gula naked, and 

 transformed into a sort of pouch, extremely developed in Pelicans, and well seen in Cormorants. 

 The next commonest is definite bareness of lores, as in all Herons and Grebes; in the former 

 including the wliole circum-orbital region. A little orbital space is bare in many birds, as vul- 

 tinine Hawks and some Pigecms; species of Grouse have a bare warty supra-orbital space. 



