_Habitat in_ Europa _arctica_." From referring to the literature he quotes, there can, of course, be no doubt as to what species he refers. The most detailed descriptions are probably those given in the New Edition of Naumann (see above), where also a list of literature and figures is given, fully seven folio pages long! As regards the difference in the sexes little is known, because very few specimens exist of which the sex has been ascertained. We find, however, some with the grooves and ridges on the bill more marked, and the grooves purer white, while others have the grooves of a dirtier white and less strongly developed; as these latter are apparently mostly smaller, I think they must be females, the former males. In this case my two specimens would be females, and the one now in Professor Koenig's possession an adult male. Probably somewhat similar seasonal changes took place as in _Alca torda_, and Professor Blasius (l.c.) has described them. It must, however, be remembered, that the date of capture is known of but a few examples, and that by far the majority of all those that exist in collections have been killed in spring, on their breeding-places. Nobody can doubt that the Great Auk is extinct. The last specimens were obtained on Eldey, near Iceland, in 1844, and the seas and islands {155} where the great bird used to live are frequented by vessels every year. It is true that a certain Lorenz Brodtkorb told that in April, 1848, he saw four Great Auks, of which he shot one, near the Varanger Fjord, east of the North-Cape, but Professor Newton and Wolley have, in 1855, had an interview with Brodtkorb, and came to the conclusion that he saw and shot the Great Northern Diver. This is the more likely to be the case, as the occurrence north of the Arctic Circle is as yet uncertain, the finding of Great Auks both on the island of Disco (west-coast of Greenland) and on Grimsey and Mevenklint on the north coast of Iceland being open to doubt. From sub-fossil and prehistoric finds, we know that the Great Auk formerly inhabited Norway and Sweden, Denmark, with Seeland, Sejerö and Havnö, the British Islands (Cleadon Hills in County Durham, Scotland, Ireland), the east coast of North America from Labrador to Florida. In historic times we know of the occurrence on the islands near Labrador, Greenland--where it certainly used to breed on the east coast, but was probably only of rare and exceptional occurrence on the west coast--Iceland, the Faröe Islands, Fair Island between the Orkney and Shetland Islands (doubtful), Orkneys (Papa Westra), St. Kilda, Skye, and Waterford Harbour in Ireland. But as breeding stations within historic times the following only are absolutely certain:-- 1. Funk Islands near Newfoundland. 2. Iceland (Geirfuglasker, Grimsey, Eldey). 3. Faröe Islands. 4. St. Kilda. 5. Orkney Islands.