1888.] HISTORY OF CHRISTMAS ISLAND. 525 



The adult birds are dark slate on the upper parts except for a 

 band of rufous brown at the back of the neck. Below they are of a 

 fine rufous brown, barred with white on the belly. 



The bird belongs to the genus Urospizias^ (the amended form of 

 JJrospiza, the name which Kaup applied to this group of Goshawks), 

 which contains some 20 species. They are most numerous in the 

 Austro-Malay region — where the Moluccas and Lombok mark the 

 western limit of the range. Elsewhere species are found in the 

 Marianne Islands, the Fijis, New Caledonia, Norfolk Island, and in 

 Australia and Tasmania. There are several of these species to which 

 the Christmas Island bird is closely related, though it differs from 

 them as much as they differ from one another. 



The nearest relation appears to be U. griseigularis from the 

 Moluccas, from which it differs in adult plumage in possessing the 

 crown of the head not paler than the back, the slate tinge on the 

 upper breast, and the brown bars on the lower part of the belly and 

 lower tail-coverts, sharply defined and edged with slate, not obscure 

 and plain brown. The difference between the young birds is more 

 marked. The Moluccan bird has the back almost uniform, not 

 mottled, the throat with a median and two lateral lines of longitudinal 

 streaks, the breast longitudinally streaked with brown and the belly 

 with distant transverse bars which are uniform brown, not rufous, 

 in the centre. 



In the collection of the British Museum are two skins which, by 

 the slaty tinge on the back and the indications of the rufous nape- 

 band, are evidently acquiring the adult plumage. Among the worn 

 longitudinally streaked feathers at the sides of the breast are new 

 close-webbed ones which are white with brown pale-centred bars 

 very hke those on the breast of the immature Christmas Island 

 bird. This appears to be an indication that the transverse barring 

 of the underparts, which is found in the young plumage of several 

 members of the group, is a later acquired character which many 

 species never assume. The longitudinal streaking, on the other hand, 

 which occurs widely in this family of birds, must on this view be 

 regarded as the more primitive character. In our bird this stage 

 appears to be passed over altogether. 



NiNOX NATALIS, Sp. nOV. 



Supra ritfo-fulvescens, cervicis lateribus et supracaudalibus sparse 



pallide maculatis ; fronte, loris et mento pallidis ; alls fuscis 



pallidius fasciatis, et fascia albida ohiiqua; tectricibus secon- 



dariis in poyoniis externis albido fasciatis ; rectricibus fuscis, 



fasciis pallidioribus circa decern ; subtus alba, rufo-fuscescente 



fasciuta, fasciis inierfasciisque cequalibus ; subalaribus subrufo- 



fuscescentibus, obscurius maculatis; metatarso omnino plumis 



vestito. 



Adult male. Crown, nape, back, upper tail-coverts, and lesser 



upper wing-coverts uniform red tawny brown, with here and there an 



1 Cf. J. H. Gurney, ' List of the Diiu-nal Birds of Prey,' 1884. 

 Pkoc. Zool. Soc— 1888, No XXXVl. 3(i 



