PHALA CEOCOBA CID^ : CORMORANTS. 
731 
OS uncinatitm, a peculiar skull-bone occurring in nearly all the petrels, the turacous (Musopha- 
gidce)^ and many cuckoos; and liere only the stomach develops no pyloric cavity. Coeca 2, 
but very small. Sternum very broad for its length, the furculum firmly anchylosed, the poste- 
rior border entire. The femoro-caudal and ambieris are present ; the accessory femoro-caudal, 
semitendinosus, and its accessory are absent. 
The frigates are maritime and pelagic birds of most warm parts of the globe. Their 
general contour is unique among water-birds, in the immense length and sweep of the wings, 
length of the forked tail and extreme snuillness of the feet. In command of wing they are 
unsurpassed, and but few birds approach them in this respect. They are more nearly 
independent of land than any other birds excepting albatrosses and petrels, being often seen 
hundreds of miles at sea, and delight to soar at an astonishing elevaticm. They cannot 
dive, and scarcely swim or walk ; food is procured by dashing down on wing with unemug 
aim, and by harassing gulls, terns, and other less active or weaker birds until they are forced 
to disgorge or -di'op their prey. Their habit is gregarious, especially during the breeding 
season, when thousands cougr^ate to nest in low 
thick bushes by the water's edge. The nest is a 
shallow flat structure of sticks; the eggs, two or 
three in number, are greenish -white with a thick 
smooth shell. The young are covered with yel- 
lowish-white down, and look at first as if they had 
no feet. They are fed by regurgitation, but grow 
tardily, and do not leave the nest until they are able 
to follow their parents on wing." The following is 
the principal if not the only species. 
305. TACHY'PETES. (Gr. TaxvTrerrjs, tachupetes, fly- 
ing rapidly.) Frigates. Character as above. 
761. T. a'quilus. (Lat. aquilus, dark, swarthy. Figs. 
507, 508.) Frigate. Man-of-war Bird. ^ Fig. 508. — Guiar pouch of Frigate, 
brownish-black, glossed with green or purplish, duller on the belly, wings showing brown 
and 'gray ; 9 with white on neck and breast. Length about 3.50 feet ; extent 7-00-8.00 ; 
wing 2.00; tail 1.50; bill 5 or 6 inches; tarsi 1 inch or less! S. Atlantic and Gulf Coast. 
Eggs 2-3, 2.90 X 2.00. 
58. Family PHAETHONTID^ : Tropic Birds. 
Bill about as long as the head, stout, straight, compressed, tapering, acute, paragnathous. 
Gular sac rudimentary, almost completely feathered. Nostrils small, linear, but remaining 
patulous. Tail with the two middle feathers in the adult filamentous and extraordinarily 
prolonged, the rest short and broad. Among anatomical characters it is to be noted that the 
muscles of the leg are as in Laridce, as might be expected from the outward resemblance of 
these birds to terns ; they having the accessory semitendinosus, lacking in other families of 
the order. 
The tropic bird resembles a large stout tern in general figure ; the bill, especially, being 
almost exactly like that of a tern. The principal external peculiarity is the development 
of the middle tail-feathers ; the feathering of the gular sac and the permanent patulance of 
the nostrils are other features. They are graceful birds on the wing, capable of protracted 
flight, venturing far from land. They are gregarious at all times, and nest in communities 
along coasts and on islands, in rocky places or among low trees and bushes. As implied in 
their name, they are birds of the torrid zone, though in their extensive wanderings they visit 
Southern seas, and have even been reported from beyond latitude 49° N. There are but three 
well-determined species : P. flavirostris, P. cethereus, and P. ruhricauda. 
