NATATORES. 503 



centre of the tertiarics and flank-feathers deep blaek ; the 

 whole of the remainder of the phiinage silky white, with a 

 rich roseate tinge, especially on the back ; shafts of the 

 primaries black from the base to within an inch of their apex ; 

 shafts of the lateral tail-feathers black to within half an inch 

 of the tip ; two centre tail-feathers white at the base and rich 

 deep red for the remainder of their length, which extends to 

 eighteen inches, their shafts black ; irides black ; bill vermilion, 

 with a black streak running through the nostrils, and a narrow 

 line of faint blue at the base of both mandibles ; tarsi and the 

 base of the toes and webs faint blue, remainder of the toes 

 and webs black. 



The young birds for the first year are very different from 

 the adults, being of a silky white without the roseate blush, 

 with the whole of the upper surface broadly barred with black 

 and with the black of the shafts of the primaries expanded into 

 a spatulate form at the tips of the feathers. 



Genus SULA, Brisson. 



The birds hitherto included in this genus have recently 

 been divided into no less than three genera, iSala, Bysporus, 

 and Piscafrix. They inhabit nearly every part of the globe, 

 and four fine species appertain to the Australian fauna, since 

 they not only frequent the seas adjacent to the shores of that 

 country, but all of them resort to its rocks and islands for the 

 purpose of breeding. 



Our own well-known Bass Rock is inhabited yearly by a 

 bird of this genus bearing the trivial name of Solan Goose, 

 which must be familiar to every reader of the present Hand- 

 book, at least to all those who reside in the British Islands. 

 These birds are also well known by the name of Boobies, an 

 appellation they have obtained from their apparently stupid 

 insensibility to danger. 



