324 LARIDE®, SKIMMERS. —GEN. 295. 
pressed, 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 hinge at the forehead. There are cranial peculiarities. Conformably 
with the shape of the mouth, the tongue differs from that of other Longipennes in 
being very short and stumpy, as in kingfishers, and the Steganopodes. The wings 
are exceedingly long, and the flight more measured and sweeping than that of terns ; 
the birds fly in close flocks moving simultaneously, rather than in straggling com- 
panies. 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 of terns, as are all 
points of structure excepting those above specified. Besides the following, there 
are only two species: &. flavirostris and R. albicollis, of Asia. 
295. Genus RHYNCHOPS Linneus. 
Black Skimmer. Cut-water. Glossy black, the forehead, sides of head 
and neck and all under parts pure white, or rosy-tinted ; tail ashy and white ; 
bill red, black-tipped; feet orange. Young: grayish-black or dull brown 
above, varied with white ; bill yellow, dusky-tipped. Length 16-20 inches ; 
extent 3-4 feet ; wing 13-15; tail 4-5, forked ; under mandible 34—4$, upper 
24-3. Coast of South Atlantic and Gulf States, very abundant; frequently 
to the Middle States, and even straying to New England. W11s., vii, 85, pl. 
60, f.4; Nurr., ii, 264; Aup., vii, 67, pl. 428; Lawr. in Bp., 866. NiIGRA. 
Family PROCELLARIIDA. Petrels. 
Nostrils tubular. Bill epignathous; its covering discontinuous, consisting of 
seyeral horny pieces separated by deep grooves. Hallux small, elevated, func- 
tionless, appearing merely as a sessile claw, often minute, absent in two genera. 
These are oceanic birds, rarely landing except to breed, unsurpassed in powers 
of flight, and usually strong swimmers; excepting the sea-runners, none of them 
dive. With the same exception, the wings are long, strong and pointed, of 10 stiff 
primaries and numerous short secondaries ; the humeral and ante-brachial portions 
are sometimes extremely lengthened. ‘The tail is short or moderate, of less than 
20 feathers, of variable shape. The feet are usually short, with long full-webbed 
front toes, and a rudimentary hallux, as above stated, or none. In size, these birds 
vary remarkably, ranging from that of a swallow up to the immense albatrosses, 
probably unsurpassed by any birds whatever in alar expanse, and yielding to few 
in bulk of body. The plumage is compact and oily, to resist water; the sexes 
appear to be always alike, and no seasonal changes are determined ; but some color 
variation with age, or according to individual peculiarities, certainly occurs in most 
cases, and in the Pufini, for instance, in which some currently admitted species are 
uniformly fuliginous, it is not proven that this feature is not temporary, as in the 
jacgers. The food is entirely of an animal nature, and fatty substances, in partic- 
ular, are eagerly devoured ; when irritated, many species eject an oily fluid from the 
mouth or nostrils, and some are so fat they are occasionally used for lamps, by 
running a wick through the body. The eggs are few, or only one, laid in a rude 
nest, or none, on the ground or in a burrow. Petrels are silent birds, as a rule, 
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