PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 207 



appear to raise doubts about tlie specific value of hewicMi* (Yerli. Zool. 



Bot. Ver. Wien, 1879, p. 256), that " only the shorter tarsus and middle 



toe can be given as distinctions"; but 



even this mark cannot be employed with 



individuals that have not yet reached 



their full size. I have therefore looked 



about after another distinctive mark, 



and believe I have found one, which is 



characteristic in all ages. I* 



What there is most peculiar in 0. he- 1 



wicMi, when comi^ared with the Hooper, § 



is without doubt the higher and rather s" 



shorter form of the bill, and on the whole 



the bill is that part in which we can 



expect to find the most essential char- 

 acters in these birds. 



I have had the beaks of two full- 

 grown young birds, in gray plumage, 



photographed, the one of Bewick's, 



the other of the Hooper, so that the 

 former, in order to be more easily com- 

 pared, is so much enlarged that it has 

 obtained exactly the same size as the o 

 latter. Figs. 15 and IG are taken very | 

 carefully after these photographs. I 



If one takes the distances from the |i 

 tip of the bill to the hind border of the |' 

 nostrils, and from this point again to 

 the mouth, in the one figure, between 

 the feet of the dividers, and places these 

 measurements on the other figure, it 

 will be very easy to convince oneself 

 that the nostrils in bewicMi lie nearer 

 the tip of the bill than in the Hooper, 

 which can also be expressed thus, viz, 

 that in the Hooper the distance from the mouth to the hind border of 

 the nostrils is equal to the distance between this and the hind border 

 of the nail of the bill, whilst in hewiekn the former distance is equal to 

 that between the hind border of the nostrils and a point on the middle 



*When Dr. Finsch, ], c, in his comparative table of the dimensious, quotes *lie 

 measurements of Professor Schlkgel, and thereby makes out that the difference in size 

 between cygnus and hewickii is only slight, it should not be forgotten that one of the 

 specimens which Professor Schlegel measures as ctignus is only a female of hewicUi, 

 and, moreover, a very small one, too, as is fully evident from my table. 



The mistake of Professor Schlegel is the more strange frojii -the fact that he in his 

 catalogue (p. 81) expressly adverts to the peculiar extension of the yellow color on 

 the biU being exactly that of the typical hewickii. 



