NATURAL SCIENCES OF PHILADELPHIA. 151 



iug white ; and often is not uniform in tint, but is minutely undulated or 

 punctulated with lighter and darker shades. 



The front, lores, lower part of cheeks, and whole under parts, including the 

 lower tail coverts, are white. The lateral rectrices are on their inferior aspect 

 chiefly white, with some light cinereous marbling. 



In general terms it may be stated that the older the bird, the clearer and 

 purer is the cinereous, and the more trenchantly defiued are the boundaries 

 of the several differently colored areas ; the difference in this respect being 

 especially notable in the forehead and sides of the breast. 



Young birds are all over of a pretty uniform deep brownish ash, or fuligin- 

 ous cinereous ; inclining to smoky brown on the wings and tail. 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 remain- 

 ing white. The transocular dark fascia is always present. But the chin and 

 face are much mottled with whitish ; and in specimens otherwise wholly dark 

 on the under parts, the chin aud throat may be chiefly white, striatulated 

 with ashy brown. 



Moulting specimens, or those in poor plumage from the age and worn con- 

 dition of the feathers, show scarcely a trace of cinereous on the wings and 

 tail, these parts being of a dull brownish, more or less tending to gray. The 

 same tendency to brownish or grayish instead of cinereous is observable on 

 other parts. Sometimes a pure white chin and throat coexists with complete 

 dusky clouding of the other under parts.* 



The bill and feet hardly differ in color with age. The bill is black; the 

 tarsus, basal half of inner toe and contained web, flesh colored : (dull yellow- 

 ish when dry ;) all the rest of the toes and webs, with all the claws, black. 



Dimensions. (No. 1678, Phila. Acad., J. Gould.) Bill (chord of culmen) 

 1-10. Height at base -45 ; width slightly less. Tarsus 1-33. Outer toe and 

 clawl'75; middle about the same, inner 1*50. Wing average 1O00 ; but 

 may range from 9 - 50 to 10-50 ; tail4"50 ; the graduation of the rectrices about 

 1'30. These are nearly the average dimensions of six examples. 



There is a specimen, No. 15,706, in the Smithsonian Museum from the 

 Antarctic Ocean, by Mr. T. R. Peale, which, with the size and general appear- 

 ance of mollis differs as follows : The under surfaces of the wings are, except just 

 along the edges, purely and uninterruptedly white ; as much so as in C okii. 

 The inner vanes of all the primaries, instead of being simply duller and grayer 

 than the outer, have trenchantly defined pure white areas ; these white spaces 

 occupy the whole of the webs at the base ; as they extend more towards the 

 apex they become less wide, leaving a narrow space of dark color along the 

 inside of the shafts ; apically they terminate with an acutely pointed outline, 

 which stretches towards the tip of the feather, and is bounded internally and 

 externally by dark colored portions of the feather. The general pattern is 

 exactly that seen in the primaries of most Lari ; and the definition of the two 

 colored areas is as strict. In other respects the bird is like a quite young 

 mollis, being dark colored both above and below ; but the tint of the cloud- 

 ing below is more intensely sooty than in any specimen of typical mollis I have 

 9een ; and there is this peculiarity in addition, that the under tail coverts 

 remain pure white. 



I do not wish to introduce a new name upon the above basis ; though pos- 

 sibly in any other family than the very one of the Petrels I would do so. The 

 points which would consiitute its specific characters are elucidated in the pre- 

 ceding paragraph ; and should the differences above pointed out be substan- 

 tiated as persistent in other specimens, it would, I think, then be proper for 

 the ornithologist who makes the verification to forma ly introduce the species. 

 The specimen in question before me is the only one contained in the United 



# In which condition is the type of "gularis," Teale, 



[May, 



