Brewster on a Pet rel new to North America. 93 



have seen ; and there is this peculiarity in addition, that the under 

 tail coverts remain pure white." 



This specimen had been previously described bv Peale (Zool. 

 U. S. Expl. Exped.. 1S48. p. 299) under the name of Procella- 

 rict gttlaris. but Dr. Cones, after expressing his doubts as to its 

 probable relationship, provisionally referred it to ^£\ mollis,* 

 and there the matter has rested, the type, up to the present time 

 remaining unique. 



The above description proved so nearly satisfactory that upon 

 first reading it I felt little doubt as to the relationship of the bird 

 in hand : but all uncertainty on this point has since been removed, 

 for through the kind offices of Mr. Ridgwav, the Smithsonian 

 specimen "No. 15,706" is now before me. A comparison of 

 the two at once establishes their perfect specific identity. The 

 differences that obtain are just those which would be expected 

 when the relative ages of the specimens are considered. Peale's 

 example is a young bird, apparently in its first year ; while mine, 

 if not an adult, is certainly much older and probably in nearly 

 mature plumage. Generally speaking, it may be said to differ 

 from the type in having the predominating areas above pure cin- 

 ereous instead of plumbeous ; the crown and forehead much 

 mixed with white : the lores and a conspicuous superciliary stripe 

 pure white, unmingled with darker color ; the transocular faciae, 

 though equally dark, much more restricted ; and the white areas 

 below. t considerably more extended and of a purer character. 



Of the stages in y£. mollis. Dr. Coues says : "the older the bird 

 the clearer and purer is the cinereous and the more trenchantly 

 defined are the boundaries of the several differently colored areas ; 

 the difference in this respect being especially notable in the fore- 

 head and sides of the breast. Young birds are all over of a 

 pretty uniform deep brownish ash or fuliginous cinereous ; in- 

 clining to smoky brown on the wings and tail." 



And now a word as to the relationship which these interesting 

 specimens bear to ^Pl. mollis. Of the latter I have only a single 

 specimen, an adult, kindly furnished by my friend Mr. Allen, 

 from the collection of the Cambridge Museum of Comparative 

 Zoology. But the testimony which it affords, taken in connection 



* Upon looking more closely into the earlier history of the case I find that this ar- 

 rangement was first instituted by Cassin, who, in the second edition of the U. S. Expl. 

 Ex., places Peale's specimen under Procellaria mollis. 



f The type of gularis has a pure white throat and light breast. 



