| EXTERNAL PARTS OF BIRDS.— TOPOGRAPHY. 95 
between them is called the interscapulare (fig. 25, 10) ; it is often marked, as in the chipping 
sparrow, with streaks or some other distinctive coloration. A part of dorsum, lying between 
interscapulare and uropygium, is sometimes recognized as the “lower back” (Lat. tergum); but 
this distinction is not practically useful. To uropygium probably also belong the feathers of 
the pteryle femorales, or at any rate these are commonly included with the rump in descrip- 
tions; but they more properly represent the flanks (Lat. ilia, or hypochondria) ; that is, sides 
of the rump. They are sometimes the seat of largely developed or otherwise peculiarly 
inodified feathers, as the snowy flank plumes of the white-bellied swift (Panyptila saxatilis) or 
violet-green swallow (Tachycineta thalassina), which meet over the rump. The whole of 
noteum, taken together with the upper surfaces of the wings, is called the mantle (Lat. stragu- 
lum, a cloak) ; often a convenient term, as in describing gulls and terns for example. In like 
manner, the 
Fig. 25 — Topography of a Bird. 1, forehead (/rons). 2. lore. 8, cireumocular region. 4, crown (vertex). 
5, eye. 6, hind head (occiput). 7, nape (nucha). 8, hind neck (cervix). 9, side of neck. 10, interscapular region. 
11, dorsum, or back proper, including 10. 12, notwum, or upper part of body proper, including 10, 11, and 13. 
13, rump (wropygium). 14, upper tail-coverts. 15, tail. 16, under tail-coverts (crisswm). 17, tarsus. 18, abdo- 
men. 19, hind toe (hallux). 20, gastreum, including 18 and 24. 21, outer or fourth toe 22, middle or third toe. 
23, side of the body. 24, breast (pectus). 25, primaries. 26, secondaries. 27, tertiaries; nos. 25, 26, 27 are all 
remiges. 28, primary coverts. 29, alula, or bastard wing. 30, greater coverts. 31, median coverts. 32, lesser 
coverts. 33, the ‘‘ throat,’ including 34, 37, 38. 34, jugulwm or lower throat. 35, auriculars. 36, malar region. 
37, guia, or middle throat. 38, mentum, or chin. 39, angle of commissure, or corner of mouth. 40, ramus of 
under mandible. 41, side of under mandible. 42, gonys. 43, apex, or tip of bill. 44, tomia, or cutting edges of 
the bill. 45, culmen, or ridge of upper mandible, corresponding to gonys. 46, side of upper mandible. 47, nostril. 
48 passes across the bill a little in front of its base. 
Gastreum is subdivided into regions, called, in general terms, breast (Lat. pectus ; fig. 25, 
24), belly (Lat. abdomen ; fig. 25, 18), and sides of the body (Lat. pleura ; fig. 25, 23). The 
“sides” or pleure belong really as much to the dorsal as to the ventral aspects of a bird’s 
body ; but in consequence of the underneath-freighted shape, the line we drew passes so high 
up along them, that they are almost entirely given over to gastreum. The breast begins over 
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