PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 223 

 IV. — Comparative table of dimensions. 



Species. 



■C columba 

 ■C. (jrylle . . 

 <J. mandtii 



Specimens. 



Average measurements of 6 adults.. 

 Average measurements of 7 adults . 

 Average measurements of 11 adults. 



-a 2 

 fee a 



7} 



B 



3 





^ 



mm. 1 mm. 

 10.2 



9.6 



8.4 



mm. 

 35.3 I 47.8 

 32.0 I 42.5 

 31.8 1 41.7 



By the discover}' that the American species is mandtii, our ideas as 

 to the 



GEOGRAPHICAL DISTRIBUTION 



■of the three species must be considerably modified. Large areas must 

 be detracted from C. grylle, and the range of mandtii extended corre- 

 spondingly. 



Cepphus mandtii 



is circumpolar in its distribution. It is the form known to inhabit 

 Spitzbergen (Malmgr. Newt. Heugl., U. S. Nat. Mus.) and Novaja 

 Semlja (Heuglin); it has been found breeding in Greenland (Faber, 

 Finsch, U. S. Nat. Mus.), and also — and, as it seems, exclusively — 

 on the opposite side of Davis Strait and BafQn's Bay (Kumlien, Feilden, 

 U. S. Nat. Mus.). It is this species which breeds in abundance on 

 Herald Island, north of Bering's Strait (U. S. Nat. Mus.), and there is 

 not the slightest doubt that it is the same species which was found by 

 Mr. E. W. Nelson on Wrangel Island. Nor is it reasonable to suppose 

 that the Guillemot met with hy the "Jeannette" party, breed iug on 

 Bennett Island, one of the New Siberian Islands, belonged to another 

 species, and the "few Black Guillemots" found by the naturalists ot 

 the "Vega" expedition, on Preobraschenij Island, on the coast of the 

 East Taimyr Peninsula, were in all probability the same. In the old 

 world Mandt's Tyste does not seem to breed outside of the Arctic Seas, 

 while on the American side of the Atlantic its breeding range extends 

 considerably further southwards, being, as it seems, from the propor- 

 tion of the specimens in the National Museum, the most numerous form 

 in the northeastern coast of North America, although no specimens 

 in breeding plumage are from any locality south of Labrador. The 

 National Museum possesses adult birds in breedin-g plumage from St. 

 George, Hudson's Bay, collected by Mr. Drexler, and also half fledged 

 young from the same localit3\ 



During winter many individuals remain at the place of their birth, 

 provided open water be found in the neighborhood, while many go 

 further south The National Museum has winter specimens from St. 

 Michael's and Point Barrow, in Alaska, from Eastern North xVmerica, 

 Cumberland Sound, and Iceland. In all probability, a portion of the 

 Spitzbergen birds winter on the coast of Northern Norway, and those 



