COUES, BIRDS OF NEW ENGLAND. 59 



but that such is the case is purely a matter of conjecture, 

 and would be an exchange of one doubtful opinion for 

 another. The other is, that it is an immature stage of 

 L. glaucus. The color of the bill and some other fea- 

 tures tend to confirm this latter supposition. I am some- 

 what familiar with the " theory of variation " which ob- 

 tains among Gulls during their progress toward maturity ; 

 but do not now recollect an instance in which the bluish 

 pearl of the upper parts of those species, which, like 

 glaucus, finally attain this color, is not apparent at an age 

 evidently reached by the specimen in question. More- 

 over, if such a state of plumage as that just described is 

 a normal stage of glaucus during its adolescence, it is 

 rather singular that I should have met with no description 

 of such a condition in my tolerably thorough study of 

 Larine bibliography. For the present, therefore, I con- 

 tinue to give credence to the existence of a large pure 

 white gull, for which I have adopted the above name ; 

 being prepared, however, in view of the extreme uncer- 

 tainty of all matters ornithological, and especially Larine, 

 to retire from my position when the first good evidence of 

 its unsoundness is presented. 



No. 1132. Essex Co. S. Jillson, 1856. 



[Note. The Larusfuscus is given by Peabody (p. 380) as found off 

 tlie coast of Massachusetts, and by Linsley (p. 271) as from Stoning- 

 ton, Conn. These are, doubtless, erroneous identifications. There is 

 no good evidence of the occurrence of this European species on our 

 coasts.] 



Ghrmcocephalus atricilla Lawr. — Laughing Gull. Res- 

 ident. Not abundant. "A few breed about the islands." 

 (Bay of Fundy, Boardm., p. 131.) Winters sparingly 

 along southern portions of the coast. 



No. 1106, young. Essex Co. S. Jillson, 1856. 



Ohroecoc&phalus Philadelphia Lawr. — Bonaparte's Gull. 

 Common ; resident, except perhaps during the breeding 

 season. By no means confined to the coast. 



No. 1107, young. Essex Co. S. Jillson, 1853. 



Rissa tridactyla Bon. — Kittiwake. Common winter 

 resident. Some probably breed off the coast of Maine. 



No. 1105, young $, winter. Essex Co. S. Jillson, 1854. 



No. 1108, adult. Essex Co. Dr. H. K. Oliver, 1854. 



The Fork-tailed Gull, Xema 8abinii Leach, doubtless 



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