The proper breeding places of this bird scarcely appear to be yet known. So common as it is both on the coasts of Spitzbergen from the Seven Islands to South Cape and on the north coast of Novaya Zemlya and America, its nest has only been found twice, once in 1853 by McClintock at Cape Krabbe in North America in 77 deg. 25' N.L., the second time by Dr. Malmgren at Murchison Bay, in 82 deg. 2' N.L. The two nests that Malmgren found consisted of depressions, twenty-three to twenty-six centimetres in diameter, in a heap of loose gravel, on a ledge of a steeply-sloping limestone-rock wall. In each nest was found only one egg, which, on the 30th July, already contained a down-covered young bird. For all the ivory gulls which have their home on Spitzbergen there were doubtless required several hundred such breeding-places as that at Murchison Bay. When to this is added the fact that we never in autumn saw on Spitzbergen any full-grown young of this kind of gull, I assume that its proper breeding-place must be found farther north, on the shores of some still unknown Polar land, perhaps continually surrounded by ice. It deserves to be mentioned with reference to this, that Murchison Bay was covered with ice when Malmgren found the nests referred to above. Besides these varieties of the gull, two other species have been found, though very rarely, in the Polar regions, viz., _Larus Sabinii_, Sabine, and _Larus Rossii_, Richards. Although I have myself only seen the latter, and that but once (on the Chukchi Peninsula), I here give drawings of them both for the use of future Polar explorers. They are perhaps, if they be properly observed, not so rare as is commonly supposed.