Nigripes; while the circumpolar banded lemming, Dicrostonyx torquatus, which turns white in winter, represents a second genus taking its name from the double claws on one of the toes of the forefeet.
He is mostly found in the circumpolar seas.
There are three genera: (i.) Priapulus, with the species P. caudatus, Lam., of the Arctic and Antarctic and neighbouring cold seas, and P. bicaudatus, Dan., of the north Atlantic and Arctic seas; (ii.) Priapuloides australis, de Guerne, of the southern circumpolar waters; and (iii.) Halicryptus, with the species H.
Tridactyla, of circumpolar range, breeding, however, also in comparatively low latitudes, as on the coasts of Britain, and in winter frequenting southern waters.
A few, on the other hand, have a very restricted range, the Greenland right whale (Balaena mysticetus) being, for instance, limited to the zone of the northern circumpolar ice, while no corresponding species occurs in the southern hemisphere.
Assuming that in its circumpolar origin the North Temperate flora was fairly homogeneous, it would meet in its centrifugal extension with a wide range of local conditions; these would favor the preservation of numerous species in some genera, their greater or less elimination in others.
The land mammals of Greenland are decidedly more American than European; the musk-ox, the banded lemming (Cuniculus torquatus), the white polar wolf, of which there seems to have been a new invasion recently round the northern part of the country to the east coast, the Eskimo and the dog - probably also the reindeer - have all come from America, while the other land mammals, the polar bear, the polar fox, the Arctic hare, the stoat (Mustela erminea), are perfectly circumpolar forms. The species of seals and whales are, if anything, more American than European, and so to some extent are the fishes.
Of the sixty-one species of birds breeding in Greenland, eight are European-Asiatic, four are American, and the rest circumpolar or North Atlantic and North Pacific in their distribution.
The constellations that and ned unceasingly to speed across the sky were named the and er-resting ones, and the circumpolar stars, which never ing beneath the horizon, were known as the imperishables.
The circumpolar lemmings of the genera Lemmus and Dicrostonyx are noticed in the article Lemming.