REPORT ON THE BIRDS — THE PEOCELLARIID.-E. 145 



14. (Estrelata brevirostris, Less. 



Procellaria brevirostris, Less., Man. d'Orn., vol. ii. p. 611. 



(Estrelata brevirostris, Salv., Orn. Misc., vol. ii. p. 235; Proc. Zool. Soc, 1878, p. 738; 



Sharpe, Zool. Kerg., Birds, p. 24. 

 (Estrelata hidderi, Cones, Bull. U. S. Nat. Mus., No. 2, p. 28. 



[a. Young. Kerguelen.] 



The species included in Cabanis and Reiehenow's paper on the Birds collected by the 

 "'Gazelle" (J. f. Orn., 1876, p. 329), under the name Procellaria mollis, belongs here. 

 Last year I examined in Berlin the specimen brought home by the " Gazelle," and found 

 it to be of this species. 



The Challenger specimen is quite young, but interesting, as showing that these birds 

 moult at once from the downy plumage into the feathering of the adult bird. 



15. Prion desolatus, Gra. 



Procellaria desulata, Gni., Syst. Nat., vol. i. p. 562. 



Prion desolatus, Gray, H.-list., vol. iii. p, 108; Sharpe, Zool. Kerg., Birds, p. 37 (excl. syn ) ; 



Salv., Proc. Zool. Soc, 1878, p. 738. 

 Pseudqprion desolatus, Coues, Bull. U. S. Nat. Mus., No. 2, p. 32. 



[a. Male. Betsy Cove, Kerguelen. 

 Obtained January 11, 1874. Eyes black. 

 b-e. Males. Betsy Cove, Kerguelen. Eyes black. 



f. Female. Ice Barrier. 

 Obtained on February 14, 1874, 



g, h. Females. Betsy Cove, Kerguelen. 



We found nests of this species under almost every tuft of Azorella at Kerguelen. 

 They contained one egg.] 



Of the eight specimens of this species brought home by the Expedition, five are males 

 and three females. They thus offer an opportunity of testing the view advanced by Mr 

 Sharpe as to the supposed sexual difference in the size of the bill existing in these birds. 1 



In these specimens there is no tangible difference between the bills of the sexes ; 

 and as the opposite sexes of Prion hanksi, as shown by the two Challenger speci- 

 mens, are also alike as regards the size of the bills, doubts may fairly be raised whether 

 the great difference observable in the size of the bills in these birds is a sexual character 

 at all. 



1 Latham seems to have been the first author who mentioned this supposed sexual difference in Prion. After 

 describing Prion vittatus (Syn., vol. iii. p. 414), he adds : — "The female has the same plumage ; but the bill, though 

 greatly exceeding that of any other Petrel, is scarcely more than half the breadth of that of the male." 



(zool. chall. exp. — part viii. — 1880.) H 19 



