EXTERNAL PABT8 OF BIBDS. — TOPOGBAPHY. 97 



is called " cervical collar," to distinguish it from the guttural or jugular " collars " or rings of 

 color. Nucha is frequently similarly marked with a " nuchal band ; " often special develop- 

 ments there take the form of lengthening of the feathers, and we have a " nuchal crest." More 

 particularly in birds of largely variegated colors, guttur and jugulum are marked lengthwise 

 with stripes and streaks, of which those on the sides are apt to be different from those along 

 the middle line in front. Jugulum occasionally has lengthened feathers, as in many herons. 

 Higher up, the neck in front may have variously lengthened or otherwise modified feathers. 

 Conspicuous among these are the ruffs, or tippets, of some birds, especiaEy of the grebe family 

 (Podicipedidse), and, above all our other birds, of the male ruff (Machetes putgnax). But 

 these, and a few other modifications of the feathers of the upper neck, are ,more conveniently 

 considered with those of the 



Head. — Though smaller than any of the areas already considered, the head has been 

 more minutely mapped out, and much detail is required by the number and importance of its 

 recognizable parts or regions. Without intending to mention all that have been named, I 

 describe all needed to be known for any practical purposes. 



" Top of the head" is a collective term for aU the upper surface, from base of bill to 

 nape, and laterally to about the level of the upper border of the eyes ; this is the pileum or 

 "cap" (fig. 25, 1, 4, 6) ; it is divided into three portions. The forehead, or frontal region, 

 or simply " the front " (Lat. frons ; fig. 25, 1), includes aU that slopes upward from the bill, 

 — generally to about opposite the anterior border of the eyes. Middle head or crown (Lat. 

 corona) or vertex (Lat., fig. 25, 1), includes the top of. the head proper, or highest part, from 

 the rise of the forehead to the fall of the hind-head towards nucha. This slope is the hind-head, 

 or occiput (Lat., fig. 25, 6). The lateral border of all three constitutes the superciliary line, 

 that is, the line over the eye (Lat. super, over; cilia, little hairs, especially of the brows). 

 " Crown " is often used as the same thing as pileum. The adjectives of the several words are 

 frontal, coronal or vertical, and occipital : pileum has none in use, coronal being said instead. 



" Side of the head" is a general term defining itself; it presents for consideration several 

 regions. The orbital or circumorbital region, or simply the orbit (Lat. orbis, an orb, here the 

 socket of the eyeball; fig. 25, 3), is a small space forming a ring around the eye. It includes 

 the eye, and especially the eyelids (Lat. palpebres). The points where these meet, in front and 

 behind, respectively, are the anterior canthus and posterior canthus (Gr. xavBos, kanthos, Lat. 

 canthus, a tire). The orbital region is subdivided into supra- orbital, infra-orbital, ante-orbital, 

 and post-orbital, according as its upper, under, front, or back portion is desired to be specially 

 designated. The situation of the orbit varies much in different groups of birds ; it is generally 

 midway, as said above, but may be higher or lower, jammed on toward the biU, or pushed far 

 up and back, as strikingly shown in the woodcock. In owls, the orbital region is exaggerated 

 into a great disc of radiating feathers, conferring a peculiar physiognomy. The awal or 

 auricular (Lat. auris, or auriculum, ear ; fig. 25, 35) region lies about the external opening 

 of the ear, or meatus auditorius ; its position varies in heads of different shapes, but it nearly 

 always lies behind and a little below the eye. Wherever located, it may be recognized at a 

 glance, by the peculiar texture of the feathers (the auriculars) which overlie the meatus. 

 Doubtless to offer least obstacle to sound, these are a parcel of loose-webbed little plumes, 

 which may be collectively raised and turned forward, exposing the orifice of the ear ; they are 

 extremely large and notable in those owls which have complicated external ear parts, and in 

 such they form part of the great facial disc. The term " temporal region " or " temple " is not 

 often used in ornithology, not being well distinguished from the post-orbital space between eye 

 and ear, and having nothing special about it. At the lowermost back corner of the side of the 

 head, generally just behind and below the ear, may be seen or felt a hard protuberance ; it is 

 the sharpest comer-stone of the head, being the place where the lower jaw hinges upon the 



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