404 MR. H. SAUNDERS ON THE GEOGRAPHICAL 



ponent parts of which are missing. This view is strengthened 

 when it is observed that from the Moluccas throughout part of 

 Polynesia is found its nearest ally amongst the Sooty Terns, 

 namely S. lunata, a species in which the upper parts are dark 

 grey instead of black as in S. fuliffinosa a.nd S. ancestheta. Here, 

 again, the Pacific seems to be the point of departure. 



On the coasts of Peru and Chili is found a very remarkable 

 species, Ncenia inca, typical as regards its forked tail, but raised 

 to generic rank on account of its long, curved, projecting feathers 

 resembling moustaches, and the union of the foot with the hallux. 

 It is believed to be a rock-breeding species, but little is known 

 about it. A still more highly specialized form is the snow-white 

 Gygis, which has long slender toes, w.ith deeply excised webs, and 

 a graduated tail, th.e second or third feathers being the longest, 

 in which respect it is allied to the Noddies (Anous). Oygis Can- 

 dida ranges from Ascension, St. Helena, Madagascar, Mauritius, 

 &c. to Australia, and thence through Polynesia up to the Sand- 

 wich Islands : at the Marquesas is also found a smaller and slender- 

 billed form, which I consider entitled to specific distinction, G. 

 microrhyncJia. The nidification in this genus is very peculiar, the 

 single egg being placed in any trifling depression in the surface of 

 the branch, or in a fork of a tree or even of a stout plant. In 

 making no nest these birds resemble the majority of the Sternincs ; 

 but the shape of the tail points to a relationship with the mem- 

 bers of the genus Anous, the nearest being with the two small 

 grey Noddies, A. ccertoleus (Bennett), and A. cinereus, Grould, 

 which appear to be almost if not entirely confined to the coral- 

 islands of the Pacific, where they deposit their single egg in the 

 crevices of the rocks, making no nest. Next comes a nearly black 

 Noddy with a white crown, A. leucocapillus, Gould, confined to 

 the islands between the Paumatu group and North Australia, 

 which also seems to make no nest. The record respecting these 

 and the two following species is, however, very imperfect, and it 

 is not safe to base any deduction upon what is at present known 

 of their distribution. A. melanogenys, Gray, with deep black 

 lores and greyish nape, is a widely- distributed species, being found 

 from Honduras down to Australia and Polynesia. The most 

 remarkable fact about its range is that the ' Challenger ' Expedi- 

 tion obtained it at Inaccessible Island close to Tristan d'Acunha, 

 in 37° S. lat., the home of the penguin, the albatross, and other sub- 

 antarctic species, where the even more widely-diffused Common 



