LARUS GLAUCUS, GLAUCOUS GULL. 621 



18.50 ; bill along culmen, 2.75 to 3.00 ; along rictus, 3.75 ; depth opposite nostrils, 0.80 ; 

 at angle, 0.85 ; tarsns, 3.00 ; middle toe and claw, 2.75. 



One of the largest and most powerful of the subfamily, nearly equaling in these 

 respects the L. marinus. Tbe combination of the large size and the extremely light 

 colors render it perfectly easy to distinguish it at a glance. The well-delined, rounded, 

 white apical spots of the primaries of (jlaucesccns at once separate that species. The 

 differences of leucopteru8^ as shown by the dimensions, may be seen by comparing the 

 measurements given. 



All authors are agreed as to the great variation in size which this species presents. 

 Sabine found one to measure 32 by 65 inches, with a tarsus 3.50 and a bill upward of 

 4 inches long. The dimensions given are, it is believed, about the average. 



Note. — "■ Larus hutchinsii." — lu earlier papers I recognized this as a species distinct 

 from L. glaucus, basing characters as follows: 



Adult {TV]) — Entire plumage pure white; shafts of primaries straw-yellow. Bill 

 flesh-colored, blackish on the terminal third. Feet flesh-colored. 



Young. — Head, neck, and upper parts white, mottled with light reddish-brown, ap- 

 pearing on the back as irregular patches, and on the rump as more or less regular 

 transver.se bars. Under parts nearly uniform, very pale reddish-brown ; the under tail 

 coverts barred with white. Wings and tail pure white, with yellow shafts. 



Dbnensions. — Length, 27.50; extent, 60.00; wing, 17.75; bill along culmen, 2.40; along 

 gape, 3.20 ; height at nostrils, 0.70 ; tarsus, 3.40 ; middle toe and claw, 3..50. 



The particular coloration of the bill, however, is against the supposition that the 

 bird is adult, as this coloration is the ordinary style in young birds of this group. I 

 am now disinclined to allow that the bird is anything more than some stage of L. glau- 

 cus, although it is difiicult to account for the absence of any shade of pearly-blue on the 

 mantle. In the foregoing synonymy I assign it to glaitcus, with this explanation; and 

 in further elucidation of the question I present the following remarks, just as I find 

 them in my Mss. prepared in 1863: 



" Under the above name, and by the foregoing description, I wish to indicate a form 

 of Gull as larse, or almost as large, as glaucus, differing from this species mainly in 

 being pure white all over, and in having a differently colored bill. It looks, indeed, 

 like an albino glaucus ; but, as other species of Gulls are equally liable to albinism, we 

 should not find so many albinos of glaucus to so few, if any, of other species. Glaucus, 

 as is well known, grows lighter with age, bat is never wholly pure white; at least I 

 have seen none such, nor have I found descriptions of such a condition. And, more- 

 over, the bill of an old glaucus is never of the color of what I call hutchinsii. In this 

 respect the bird is like young glaucus, leucopierus, &c. This fact excites suspicion that 

 the bird may be an immature, if not an abnormal, ///awcHS ; yet I have no more au- 

 thority for saying so than for denying that it is so. I do not know that I clearly recog- 

 nize, or could .separate, specimens of young hutchinsii (supposing it to be distinct) from 

 young glaucus, but the adults are not to be mistaken for each other. 



" I revived this overlooked species in the ' Proceedings,' as above. We have now 

 several specimens in the Smithsonian, from widely separated localities. One of them 

 was taken in winter in New York State. Other specimens are in Captain Rodgers' 

 collections, from the North Pacific, where the bird is represented to be common. These 

 are iioticeil l)y Mr. Ca.s.'-in, as above quoted. There is a New England specimen in the 

 Museum of the Peabody Academy, at Salem, Massachusetts, mentioned by me, as 

 above, in the I-^sex Institute Proceedings. In selecting a name fV)r this bird I have 

 been perplexed, rather from not knowing which one to chooser than from any dearth of 

 names. Ornithologists differ as to the .synonymy. Bonaparte (Consp. Av.) calls it 

 ' arcticus, Macgill.' and puts ' argcntatus, Sabine,' as a .synonym. Both of these au- 

 thors speak of their subjects as having a notable amount of blue on the back — the 

 latter writer especially, dwelling on this character ('back pure pearl-gray, with a good 

 deal of blue,' &c.) Their descrijitions, beyond question, refer to leucopierus, as, indeed, 

 one of them (Macgillivray) snlxsequently afliiined. Sabine gives (Mem. B. Greenland, 

 Trans. Linn. Soc. xii, 1818), under head of L. glaucus, a full and accurate description 

 of hutchinsii, which he considers as a variety of glaucus, ' caused by sickness or a 

 scarcity of supply of food. I have not been able to examine tlio original notice of L. 

 glacialis, I'xnicken ;' but Brucli, who adopts that name, sj)eaks of tlie gull-blue of the 

 ujiper |)arts. The name is therefore not to be u.sed in this connection. Bonaparte 

 gives as a synonym ' Icuconoius, A net.', though what authors lie refers to I have not 

 been able to deterniine. This name wouUl seem to belong liere. I do not know 

 whether or not it antedates hutchinsii, ])roposed in 1831, for a liird that can bo no other 

 tlian the one now under discussion. Bonaparte's Con.spectus Gaviarnm differs much 

 from bis Conspectus Avium with regard to ♦/iiis species. In the latter he admits it a.s 

 valid, assigning specific characters iind synonymy. In the former he discards it, and 

 scatters the synonymy iudiscriiiiinately among several species." 



