PEOCELLARIID^ PHCEBETRIA 505 



nest is very singularly shaped, being cylindrical with a shallow_con- 

 cavity at the top and a somewhat overhanging edge ; the single egg 

 is held in a sort of pouch whilst the bird is incubating, so that it 

 is necessary to drive the bird right off the nest before the egg is 

 dropped ; the nests are scattered about in a Penguin rookery with 

 which birds the Mollymawks seem to be on very good terms. 

 There are two eggs in the South African Mu-eum, brought by Capt. 

 Armson from the Crozet Isles. They are slightly obtuse ovals in 

 shape and a little pitted and rough in texture ; the colour is white 

 with a ring of reddish-brown freckling round the obtuse end ; they 

 measure 4-10 x 2-75. 



This Albatros appears also to breed in the Island of St. Paul in 

 the Indian Ocean; the naturalists of the "Novara" Expedition found 

 a large number of young birds among the cliffs of that Island when 

 they visited it in the month of November, but no eggs were taken. 



807. Thalassogeron layardi. Layard's Mollymawk. 



Thalassogeron layardi, Salvin, Cat. B. M. xxv, p. 450 (1896) ; Reiclie- 

 now, Vog. Afr. i, p. 23 (1900). 



Description. Adult. Crown, cheeks, rump, upper tail-coverts and 

 whole under surface, including the under wing-coverts and axillaries 

 white ; a greyish-black mark in front of the eye and extending over 

 it, the edges not sharply denned but passing into pale grey which 

 spreads over the face ; back, and sides of the neck pale grey, becom- 

 ing a dark slaty-grey on the wings and tail. Bill greyish horny, 

 darker at the tip but with no yellow ; legs pale yellow (in dried skin). 



Length about 39-0 ; wing 22*0 ; tail 8-5 ; culmen 5-4 ; tarsus 3-5 ; 

 middle toe 5'0. 



Distribution. This Mollymawk was described from a single 

 specimen from the " Cape seas " obtained by Mr. Layard and now in 

 the British Museum. I have lately examined a second example, a 

 male, obtained by Mr. J. v. O. Marais on August 23, 1899, just 

 outside the Knysna Heads and now in the Pretoria Museum. 



Genus III. PH(EBETRIA. 



Type. 



Phoebetria, fieichb., Natilrl. Syst. Vog. p. v. (1852)... P. fuliginosa. 



Bill as in Diomedea with the culminicorn and latericorn meeting 



behind the nostril tubes ; a longitudinal groove along the lower 



mandible ; tail long "and wedge shaped, the outer feathers falling 



