12 ARKIV FÖR ZOOLOGI. BAND 12. NIO 7. 



the pattern of the back, wings and tail. The dark central 

 markings of the feathers of the back are just as large and 

 sharply defined as in L. marinuSy although perhaps a Jittle, 

 but not much paler. The primaries are dark brown, paler 

 and more greyish on the inner web. They are not quite so 

 blackish on the outer web as in L. marinus, and the shafts 

 become whitish at a somewhat shorter distance from the tip 

 than in the latter, viz. about 17 cm from the tip in the 

 first and second piimaries of the hybrid, but about 21 cm 

 in the same of L. marinus. This may, however, be a variable 

 characteristic, but the difference in this respect from L. glaucus, 

 which has entirely white shafts to these primaries, is almost 

 as apparent in the hybrid as in L. marinus. The tail-feathers 

 are in their distal parts as broadly banded with dark greyish 

 brown as in L. marinus, although the markings are more 

 blackish in the latter. 



The head, neck and under parts are much lighter in 

 the hybrid than in L. marinus. The upper parts of the head 

 is quite intermediate between L. glaucus and L. marinus. 

 The hindneck of the hybrid is almost as light and faintly 

 streaked as in L. glaucus. The foreneck is rather broadly 

 spotted with dusky, but the white interspaces are wider than 

 the spöts. The flank feathers show, unlike in L. glaucus, 

 some dark bands or centres, but paler and less than in L. 

 marinus. The belly is practically unspotted, almost as in 

 L. glaucus. As a comprehension of this may be said, that 

 this bybrid young GuU offers the general aspect of a påle 

 L. marinus. 



Another specimen belonging to the Copenhagen Museum 

 is labeled: »Larus marinus X glaticus» 5 ad., Zool. Have 19.6. 

 1913.3». It is a bird just in moult to the adult plumage. 

 The small feathers are almost all new, but the quills of wings 

 and tail are old and very strongly worn. Head, neck and 

 all under parts are already pure white, only a little clouded 

 with greyish on some spöts of the hind neck, which look as 

 if the feathers had been somewhat soiled. The mantle which 

 has assumed the new plumage is slaty blackish, little if any 

 paler than L. marinus, but somewhat darker than L. affinis 

 (as well northern specimens as one from Ireland have been 

 compared). Some of the wing-coverts remain from the spotted, 

 juvenile plumage, and the white tail-feathers are strongly 



