On the Tail-feathers of the Dabchick. 
469 
163. Larus canus Linn. Common Gull. 
Tacz. p. 1033; Dresser, p. 829. 
This is another species that I include upon the authority 
of Bianchi; a specimen was obtained at Yingtzu, March 31, 
1901. 
164. Larus veg,e Palmen. Eastern Herring-Gull. 
Tacz. p. 1028; Dresser, p. 834. 
a. S juv. Steppes, near Tsi-tsi-ha. [Sept. 1886.] 
165. Podicipes ckistatus (Linn.). Great Crested Grebe. 
Tacz. p. 1251 ; Dresser, p. 877. 
Capt. Karpow procured a specimen at Yingtzu on April 4, 
1901 (Bianchi). 
XXIII.— On the Tail-feathers of the Dabchick. 
By W. P. Pycraft, E.Z.S., M.B.O.U. 
(Text-figure 10.) 
The following short account of the number and arrangement 
of the tail-feathers of the Dabchick ( Podicipes jluviatilis) 
is the result of a more minute examination of the disposition 
of these feathers, undertaken at the request of Dr. Sclater, 
and as a supplement to my paper on this subject published 
in the volume of 4 The Ibis ’ for 1907 (p. 472). 
In that paper these feathers were described as “ semi- 
plumous in character.and not, apparently, exceeding 
eight in number.” I also pointed out that they are 
arranged, not in a continuous series, or, after the fashion of 
normal tail-feathers, in a close series, but, on the contrary, 
are set in the form of a horseshoe, of which the free ends 
are directed upwards, and so lie alternately in relation one 
to another. 
This description is practically confirmed in detail by my 
later work; though I still find it difficult to decide as to whether 
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