520 Mr. P. L. Sclater on the 



of the White-billed Northern Diver obtained from the 

 Boganida district. He told me that the bird is well-known 

 far away on the tundra to the east, but is very rare on the 

 Yenisei. 



166. * CoLYMBus ARCTicus. Black-throatod Diver. 



167. * CoLYMBUS SEPTENTRIONALIS. 



My experience differs from Seebohm's, in that I found 

 the Red-throated Diver much commoner than the Black- 

 throated Diver. The former is exceedingly numerous at 

 Golchika. 



XLIV. — On the Psophia obscura of Natterer and Pelzeln. 

 By P. L. Sclater, M.A., Ph.D., F.R.S. 



(Plate XI.) 



In the account of the Trumpeters (Psophiidae) in the British 

 Museum Catalogue (vol. xxiii. p. 231), Psophia obscura of 

 Natterer and Pelzeln has been united to P. viridis Spix. 

 Knowing full well the almost unfailing accuracy of Natterer 

 and his scrupulousness in naming new species without good 

 reason, I was always of opinion that some mistake had been 

 made here ; but, no specimens of either of these species being 

 in the British Museum or in any other collection in England, 

 I have until quite recently been unable to set it right. I 

 have now the opportunity of doing so, through the kind 

 assistance of my excellent correspondent Dr. Goeldi, Director 

 of the Museum of Para. During a recent excursion to the 

 Upper Bio Capim, in the Province of Para, Dr. Goeldi 

 obtained, near the waterfall of Acary Ussana, two living 

 examples of a Trumpeter and two dead specimens, and has 

 kindly forwarded to me one of the latter, from which the 

 accompanying figure (Plate XL) has been prepared. There 

 can be little doubt, I think, both from the locality and from 

 the original description, that these birds (which Dr. Goeldi 

 informs me were all four alike) are referable to Psojihia 

 obscura, and that they are distinct from P. viridis Spix, as I 

 will proceed to show. 



