466 THE DIVING BIRDS — PYGOPODES. 



According to Yarrell, the "Rotches,"as these birds are there called, are only 

 winter visitors to the British Islands, where they seldom make their appearance 

 on the coasts except during, or after, very stormy weather, when they are forced by 

 violent and long-continuing winds to leave the rough sea and take shelter in land- 

 locked bays. In the same manner they are sometimes driven upon the coasts of 

 France and Holland. 



Captain James C. Ross obtained a specimen of this Auk as far north as latitude 

 81° ; and its only food appeared to be small thin-skinned crustaceans. Colonel Sabine 

 found it abundant in Baffin's Bay and Davis Straits ; and in latitude 76° it was so 

 numerous in the channels of water separating fields of ice, that many hundreds were 

 killed daily, and the ship's company supplied with them. All these birds in the 

 breeding-season had the under part of the neck sooty black, terminating abruptly 

 and in an even line against the white of the belly. The young ones, in all stages 

 from the egg, as soon as they were feathered, were marked exactly like the mature 

 birds ; but in the third week in September every specimen, old or young, was observed 

 to be undergoing a change, and in the course of a few days the feathers of the throat 

 and cheeks and the under part of the neck had become white. 



Mr. Kumlien found this Auk common on the north coast of Labrador, off Resolu- 

 tion Island, Grinnell Bay, and Frobisher's Straits, but did not meet with any in 

 Cumberland. It was abundant off Exeter Sound and to the northward, on the west 

 coast of Baffin's Bay, nesting as far north as latitude 78°, and perhaps farther. It 

 was very abundant on the pack ice in Davis Straits during July, and was so unsus- 

 picious that it could be caught from the schooner's deck with a net on the end of 

 a pole. 



Eggs of this species from Greenland in the Smithsonian collection are of a rounded 

 shape — one end being less rounded than the other — and of a pale glaucous-white 

 color, without spots. Three eggs measure 1.80 inches by 1.30 ; 1.85 by 1.25 ; and 1.90 

 by 1.25. 



Gents PLATJTUS, Buuxxich. 



Aim, Link. S. N. ed. 10, 1. 1758, 130 ; ed. 1-2, I. 1700, 210 (part). 



Plaulus, Brunn. Zoo]. Fund. 1772, 78 (type, Aim impennis, Linn. ).— Brandt, Bull. Ac. St. 



Petersb. VII. 1869, 203. 

 Pinguinus, Bonnat. Eur. Meth. 1790, 28 (same type; not of Br.uNN. 1772). 

 Tarda, Dumeril, Zool. Anal. 1800, 72 (same type). 

 Chenalopez, VlEILL. Notiv. Diet, XXIV. ISIS, 132 (same type). 

 Mateeoptera, Gloger, Handb. 1842, (same type). 



Gyralca, Steknstrup, Vid. Med. Nat. For. Kjbb. 1855, 114 (same type). 



Char. Largest of the family. Form heavy and robust, the wings disproportionately small, not 

 admitting of flight; tail short, pointed ; hill about as long as the head, much compressed, its 

 greatest depth equal to about half the eulmen ; culmen straight, and parallel with the commissure 

 for the basal half, then regularly curved to the gently decimate tip ; terminal half of the maxilla 

 with about six to ten obliquely transverse faintly curved grooves ; terminal half of the mandible 

 with about the same number of vertical grooves; lores completely and densely feathered, the 

 inistrils hidden beneath the lower edge of the feathered area; legs short and stout, the tarsi 

 compressed and transversely scutellate anteriorly ; web of the feet full and broad. 



Only a single species of this genus is known, and this is supposed to be now entirely extinct, 

 although a considerable number of examples are preserved in museums. 



