HIILID.K — TlIK GAXNIiTS — SILA. 



177 



(No. (;73l(!, CliristiuiiM I.; Dr. T. |[. Stukkts) : Hciul, iicik, ami upper jMirts Kenorully, tliirk 

 ;,'r,ivisli liiDwn; lower neck aiul entire lower piirtn wliile, the lliinki* Htreiikiil with },'riiyisli ; mitlille 

 cil the liack, iind upper i>art of rump, streaked with white. Older (No. liSUCtl, Callao, Pern, July 

 15, 1870 ; Dr. L. UKUTKXiiACHiiK) : Ileail, neck, oiul lower parts, white ; upp-r part^ dark K^iy- 

 jsli luDwn, the feathers (e.xcipl renii;,'es and rectrices) narrowly tipped with white; middle tail- 

 I'liiiiiirs hoary white toward hase. Hill jjurplisli, the ma.\illa paht (grayish horn-color ; feet dusky 

 (ill dried skin). Winj,', 14.(>(» inches , tail, "."r) ; culnien, 3.W) ; dejitli of hill lhrou;,'li base, 1.20 ; 

 taisiis, 1.75 ; middle tin-, 2.35. 



Ill tiie adult plumage this species presents u (piite dose resemlilance to the mature stage of 

 ;S'. htmana ; hut the very dilferent form of the liill and hare skin ahout the face; will serve readily 

 to distinguish it. The uolunition seems to lie much more constant in this species than in either 

 S. liifKijusIm or N. pimitor, the four adults before us not presenting any appn-ciahh- dilferences. 



Tile immature speciuteii from Callao, Peru, de>'cril)ed aliove, differs slightly from otlu'rs in the 

 hill being moiv slender, and of a more purplisii Ime. It is lalielled "N. i^irinjutd, T.srii. ;" but 

 wiicthcr really niriirjuta or not, there can lie little doubt that it is referable to .S. eijatnqM. 



Tills spocics was prociirod by Dr. Hryunt at thi' llalianias. It was about the size 

 (if tiic Sii/d h'uiiiijdstni, l)iit was hcavicu', and nuuv niusciilar. lie found about twenty 

 pairs brei'dinj; at Santo Domingo Key. They apparently lay their cg^s hitcM- than 

 till- i'xKiby; and the largest of the young, found early in April, were not more than 

 half grown, and the eggs of several had been freshly laid. As in tlie ease of the 

 liooliy, the number of the eggs is always two. The eggs are whiter than those of the 

 lidoiiy, the elialky covering being niueh thicker, and do luit differ much in size and 

 pidportions, the two extrenu'S measuring li.Gl) by 1.07 inches, and l.M"> by l.T.'i. 

 Tiiesc (Janncls did not associate with the other species. The young birds and eggs 

 were all in one part of the islaiul. When half fledged they were very in-etty, the 

 snowy white* down with which they were covered forming a striking contrast to tiie 

 dark lirown of the tail and wings, then just appearing. Their iiabits were precisely 

 the same as those of the IJoobies, aiul their internal structure [iresented no appreciable 

 (litlVrcnce. 



The Sula prrsomifn of (Joultl is identical with the liahama species. It was noticed 

 at sea by Dr. Pickering, between the Sandwich Islands and our western coast, in 

 long. U>~^ 30' \V. As this locality is the nearest to the coast of North America of 

 any given by the naturalists of tin* Wilkes Kxpcdition, this species may be looked 

 bir as an inhabitant of the I'acitie coast of tiie United States. It was also oliscrved 

 ill other localities in large numbers by the naturalists of that Kxiicdition, It was 

 foiiiiil most abundant at Ilondcn Island and Knderby's Island, in both of whi(di it 

 was engaged in the duties of incubation. So far as is known, it inhabits the l*a<Mtie 

 Ocean as far to the sinithwest as Northern Australia, and is more abumhmt in the 

 northern and eastern portion of its range during the season devoted to the rearing 

 of its young. 



Mr. I'eale states that these birds were first seen on the 20th of .Inly, hit. l.'{° 

 30' L'S" S., long. 89° L'o' W. Om- month afterward they were found in great num- 

 bers at HoiKb-n Island, one of the I'anmotu (Snnip, where they were sitting <in a 

 single egg each, one bird having only two eggs. They had no nest whatever, not even 

 a cavity scratched in the sand. Flat dry sandy beaches were stdected on the shores 

 of the lagoons, the female laying her egg on the Iwre ground, the male assisting in 

 the duties of incubation. They remained very gravely at their stations, regardless 

 even of man. Many were jmshed oft' their nests with the muzzles of the gmis ; they 



f.lii, 4.1.'., 1 .60, 2.1,'i, 3. 10 — as]iccinK'ii fnmi the Pauiiiotii Islands lx;ing tiic liuxcst. The snml lest is the 



Piiiivi.iii siK'ciiiioii di'scrilH'd iilxtvc. 

 Vol.. II. _ Zl 



