96 Brewster on a Petrel new to North America. 



family. This is ^Estrelata dcplippiaua. described* by Drs. 

 Giglioli and Salvador! from four specimens taken off the coast of 

 Peru in lat. 18 4' S., long. 79 35' \Y. 



In comparing their supposed species with ^E. gularis "as de- 

 scribed by Coues" the joint author's remark ; " But our species 

 differs .... in its smaller dimensions and slighter make (^E. gularis 

 being in size and make similar to ^E. mollis), in the cinereous 

 coloration of its upper, and the pure white of its lower pa its. 

 while ^E. gularis would be dark-colored above and below hav- 

 ing only the tail-coverts white." ^E. defilippiana also " has a 

 bill relatively, and in some specimens, absolutely longer." 



But these color-differences lose much of their significance when 

 it is remembered that the bird "described In' Coues" was the 

 young of gularis. My more mature specimen agrees very closely 

 with their description save that it is not " subtus omnino pure 

 alba" (this is afterwards slightly qualified by " latcribus pectoris 

 vix cinereo-tinclis ,, ). — and it is by no means improbable that 

 the fully adult gularis will be found to have the under parts 

 wholly white. f 



The discrepancy in size is less easily reconciled. The birds 

 examined by Drs. Giglioli and Salvador! are all apparently smaller 

 than either of the known examples of gularis. But still the 

 largest of the former approaches suspiciously close to the smaller 

 of the two latter: — ^E. defilippiana. wing, 9.45 : sE. gularis, 

 do.. 9. So : — and furthermore, in respect to individual size, the 

 Petrels are notoriously yariable. Nor can a comparison of 

 measurements taken by different persons always be relied upon. 

 Different methods give widely divergent results. f Scarcely two 



* " On some new Procellariidfe collected during a voyage around the world in 1865-68 

 by H. I. M.'s S. ' Magenta.' By Henry Hillyer Giglioli, Sc. D., C. M. Z. S., Naturalist 

 to the expedition, and Thomas Salvadori, M. D., C. M. Z. S., Assistant in the Royal 

 Zoological Museum of Turin," Ibis 1869 pp. 63-65. 



Rowley also gives a superb figure of the bird in his Ornithological Miscellany (Vol. I ; 

 p. 255, pi. xxxiii) but adds nothing new to an account taken from the text of the Ibis 

 article. 



t In speaking of the young of .<E. mollis Dr. Coues says : "The whole under parts 

 are not notably different from the back, though, however, the dark color only occupies 

 the tips of the feathers; their basal moiety remaining white." This statement is signifi- 

 cant in this connection, for upon examining my specimen, I find that the plumbeous 

 color below, and also on certain parts of the head and neck, is mainly confined to the 

 tips of the feathers, their concealed portions being snowy-white. 



% Since w-riting the above I find a curiously apropos illustration of this. In Peale's 

 original description of the tvpe specimen the " wing from the carpal joint " is given as 

 " ten and a half inches " while my measurement of the same bird made it 9.80, a differ- 

 ence of nearly three quarters of an inch. 



