772 



SYSTEMA TIC SYNOPSIS. — L ONGIPENNES — GA Vl^. 



Bill of Skimmer, nat. size. 



73. Subfamily RHYNCHOPiN/E: Skimmers. 



Bill hypogna- 

 thous. Among 

 ^ the singular bills 

 ^ of birds that fre- 

 quently excite 

 our wonder, that 

 of the skimmers 

 is one of the most 

 anomalous. The 

 under mandible 

 is much longer 



than the upper, compressed like a knife-blade ; its end is obtuse ; its sides come abruptly 

 together and are completely soldered ; the upper edge is as sharp as the under, and fits a 

 groove in the upper mandible ; the jawbone, viewed apart, looks like a short-handled pitch- 

 fork. The upper mandible is also compressed, but less so, nor is it so obtuse at the end; its 

 substance is nearly hollow, with light cancellated structure, much as in a toucan ; it is freely 

 movable by means of an elastic liinge at the forehead. There are cranial peculiarities. Con- 

 formably with the shape of the mouth, the tongue differs from that of other Longipennes in 

 being very short and stumpy, as m kingfishers, and the Steganopodes. The wings are exceed- 

 ingly long, and the flight more measured and sweeping than that of terns ; the birds fly in close 

 flocks moving simultaneously, rather than in straggling companies. They seem to feed as they 

 skim low over water, with the fore parts inclined downward, the under mandible probably 

 grazing or cutting the surface ; but they are also said to use their odd bill to pry open weak 

 bivalve mollusks. The voice is very hoarse and raucous, rather than strident. They are 

 somewhat nocturnal or at least crepuscular; their general economy is the same as that ot terns, 

 as are all points of structure excepting those above specified. Besides the following, there arc 

 only two species : B. flavirostris and B. albicolUs, of Asia. 



RHYN'CHOPS. (Gr. pvyxos, hrugchos, beak ; m'^, ops, the face ; well applied to the bird 

 whose beak is such an extraordinary feature.) Skimmers. Character as above. 

 R. ni'gra. (Lat. w^^ra, black. Fig. 520.) Black Skimmer. Adult $ ^ : Bill with basal 

 half carmine-red, rest black. Iris hazel. Feet carmine-red, drying yellowish, with black claws. 

 Crown of head, its sides to just below eyes, back of neck and whole upper parts, glossy 

 jet-black. Forehead, sides of head below eyes, sides of neck and whole under parts, pure 

 white, tinted rosy or creamy in the nuptial season. Lining of wings and the bordering 

 under wing-coverts, black. Primaries black, with black shafts, their inner webs duller 

 blackish, the inner four with inner webs and tips of both webs, white; secondaries white, 

 with a space of dark color on outer and small part of inner webs, increasing in amount 

 inwards, till the inner four are dark with only white tips. Tail-feathers white, the iimer 

 webs more or less obscured with dark brown. Length 16.00-20.00 ; extent 42.00-50.00 ; 

 wing 13.00-16.50 ; tail 4.00-6.00, forked about 1.50; tibiae bare LOO; tarsus 1.45; middle 

 toe and claw 1.30. Length of under mandible 3.50-4.50, of upper about 3.00 ; height opposite 

 nostrils 0.65 ; width 0.45 ; gape 4.50 or more : fused tomia or gonys of under mandible 4.00 

 or less; greatest depth of under mandible 0.60. 9 smaller than ^. Young at minimum 

 dimensions given. Young-of-the-year : Bill smaller than in adult, thinner, weaker, its 

 ridges less sharply defined, and the two mandibles of less unequal lengths. BiU brownish- 

 black for three-fourths of its length, fading into duU horn-color just at its tip, lightening into 

 more or less intense flesh-color, or light reddish, toward the base. The striae on the sides 

 of the lower mandible are as numerous as, but much less distinct than, in the adult. Tail 



