518 Mr. A, Newton on the Birds of Spitsbergen. 



grylle of Linnaeus, yet it so happened that he only caught one 

 of the chief points really diagnostic between the two species, 

 namely, the size of the bill and lower limbs, — his first character, 

 drawn from the white tips of the secondaries, not being constant, 

 as Dr. Malmgren has well shown, but arising in some cases 

 probably from the age of the feathers. However, there exists a 

 third and, so far as my experience goes, an unfailing means of 

 differentiating Cepphus mandti from C. grylle. This lies in the 

 feathers which form the conspicuous wing-spot. In the more 

 northern form from Greenland and Spitsbergen they are pure 

 white at the base, even in immature birds, while in the true 

 C. grylle, from our own islands, Iceland, and Norway, with its 

 stouter bill, these feathers are always black at the base, forming 

 an entirely, or almost entirely, concealed band across the wing- 

 spot. In C. columba, from Western America and Eastern 

 Asia, we have this band much more developed, so as to be 

 in all cases plainly visible, and towards its outer end it often 

 becomes enlarged so as to meet the black of the anterior 

 point of the carpus. In C carbo again, and in what is 

 perhaps another species*, the white spot entirely disappears. 

 Thanks to Mr. J. Hancock and my friends Messrs. G. G. 

 Fowler and Shepherd, I have had the opportunity of com- 

 paring with my own fair series of specimens from Spitsber- 

 gen a not inconsiderable number of examples of Black Guille- 

 mots from Greenland, Iceland, our own islands, and Norway. 

 The character afforded by the wing-patch is quite constant in 

 all these birds, according to the locality. The difference in 

 the lengths of the bill and legs seems subject to some variation ; 

 and as I do not think any great dependence can be placed upon 



* I refer to a specimen in the British Museum, marked " Uria carbo," 

 but which wants the white eye -patch of that species, and is entirely black 

 all over. This specimen was bought of Mr. Argent, and said to come from 

 Iceland, which is just possible, since Faber speaks of an entirely black 

 variety of Uria grylle from that island (Isis, 1827, p- 639). What, and 

 when described, is " Uria unicolor, Benicken"? 1 cannot trace it back 

 beyond a note of Brehm's (Isis, 1826, p. 988). Under the name of Uria 

 inotz/eldi Benicken described a Guillemot entirely black, but differing from 

 U. grylle by being much larger (Isis, 1824, pp. 888, 889). The British 

 Museum bird is much the same size as that species. 



