554 LARUS ARGENTATUS. 



white ; all more or less tipped with dull white ; the 

 inner secondaries and theiv coverts barred at the end. 

 The tail-coverts are whitish, barred with very pale brown ; 

 the tail-feathers white, with irregular brown spots at the 

 base, deep brown toward the end, and tipped with brownish- 

 white. The throat is white ; the lower surface in general 

 Avhitish, with indistinct spots and streaks of very pale brown ; 

 the axillaries dusky-ash, with spots of very pale brown on 

 both webs ; the lower tail-coverts white, with a few bars of 

 brown at the end. Length 25 ; bill 2-j^, its height -j-^„ ; 

 tarsus 2-^; middle toe 2-|%-. 



Having seen many Gulls of a much larger size than is 

 usual in Larus argentatus, I was led to suspect that two 

 distinct species might have been confounded under that 

 name. An examination of several specimens showed that, 

 although these large individuals are precisely similar in their 

 plumage, they differ considerably in the form of the bill, 

 which is much stronger, higher, and with a greater promi- 

 nence on the lower mandible. The tarsi are stouter, a little 

 longer, as are the toes, and the small scales and reticular 

 spaces on the interdigital membranes are somcAvhat smaller, 

 or at least less distinct and less prominent. But such differ- 

 ences, if we judge from analogy, are not sufficient to constitute 

 species. Individuals of the Glaucous and Black-backed Gulls 

 differ quite as much ; and among land-birds the Golden 

 Eagle, Sea Eagle, Raven, Blackbird, Bullfinch, and very 

 many others, exhibit differences in size, as well as in the form 

 and magnitude of the bill, still greater. If species are to be 

 formed on such grounds, Larus marinus, L. glaucus, L. leu- 

 copterus, L. canus, will each constitute at least two species. 

 To describe this large race of the Herring Gull would be 

 merely to rejieat what I have said respecting it. Yet having 

 two individuals before me, one from the Firth of Forth in 

 'vinter plumage, the other from Grand Manan, in the Gulf 

 of St. Lawrence, I may without impropriety give a short 

 comparative account of them. Supposing them to represent 

 a species, I would define it thus : — 



Bill tAvo inches and ten-twelfths along the ridge, Avhich 

 is a little raised above the nostrils, and much dccurvcd 



