proofs that the bird colony furnished them with abundance of fattening food. The following year this locality was abandoned by the shags, who established themselves on a swamp by the Purakanui; this likewise was deserted at the next breeding season. Why? If this change of quarters was rendered necessary by the presence of vermin or filth, how is the guano island built up, unless, indeed, the salt breezes of the ocean befriend the birds by destroying their parasitic tormentors.

Art. XII.—Notes on an Egg of Alca impennis, Linn., in the Collection of the writer. By T. H. Potts. [Read before the Wellington Philosophical Society, July 16, 1870.] Alca impennis, Linn.; Great Auk, or Gare-fowl; the Geir fugl of the Iceianders;—is the rarest of the Alcidœ, and probably also, it is the rarest bird of the northern hemisphere. Various authors have described it as living, except during the breeding season, almost habitually at sea, where its wondrous powers of swimming and diving procured for it a constant supply of food; we know from good authority that formerly it was to be found at St. Kilda, the Orkney and Faröe Islands, Iceland, etc., but however numerous the flocks then met with, in various parts of the stormy northern seas or its rocky ice-bound shores the Gare-fowl rapidly became scarce. Perhaps its numbers were diminished to satisfy the craving appetites of hal-frozen whalers and sealers, whose visits too would most probably take place during the breeding season, when the brief summer opened up a track for the vessels through boisterous seas, haunted with floating icebergs. I think Henry Hudson, the old navigator of those inclement seas, intended the Gare-fowl when he wrote:—“They killed and brought with them a great fowle, whereof there were many and likewise some eggs.” There was evidently no close time or fence month observed for the Great Auk; bird and egg was equally welcome to those “toilers of the sea.” So rare at last became this sea-fowl, that the only specimen the British Museum possessed for many years, was the bird obtained by Mr. Bullock, and which was purchased at his sale, May, 1819. The curious naturalist will find in the catalogue of that great sale of zoological curiosities:—“Lot 43; Great Auk (Alca impennis), a very fine specimen of this exceedingly rare bird, killed at Papa Westra, in the Orkneys, the only one taken on the British coast for many years,” etc. So long a period has elapsed since a living specimen has been observed, that many naturalists, amongst them Professor Owen, are inclined to regard its extinction as an accomplished fact, for, notwithstanding the scientific explorations, more or less exhaustive, which have characterized the various Arctic expeditions, not a single instance of the occurrence of the Gare-fowl is recorded. From notes and observations of various travellers, sportsmen, and collectors,