510 SIR VICTOR BROOKE AND MR. B. BROOKE [June 15, 
all that is known of the large Argali Sheep of Central Asia, in the 
hopes of determining the Thian-Shan species, and of ascertaining 
what may be regarded as established facts respecting the differentia- 
tion and distribution of the allied forms. 
This study has convinced us that our knowledge of the physical 
geography and fauna of Central Asia is as yet far too inexact to 
admit of any thing more than a mere statement of bare facts. We 
have therefore concentrated our efforts upon the task of placing all 
the facts that we have been able to gather in as easily accessible a 
form as possible, without attempting to estimate the exact value of 
characters of the origin and extent of which we at present know but 
little. Many of the specimens collected by the Yarkand Mission are 
now in London, and we have had the fullest opportunity of examining 
them. ‘To Mr. Edwin Ward our best thanks are especially due for 
the many facilities which he has offered to us, at, we fear, consider- 
able inconvenience, for studying the specimens committed to his 
charge. 
By far the most important recent contribution to our knowledge 
of the subject before us is due to the laborious and careful researches 
of Mr. N. A. Severtzoff, the results of which are published in the 
‘Transactions of the Imperial Society of Naturalists of Moscow,’ 
vol. vili., and also in a separate work entitled ‘ Vertikalnoe e Goro- 
yontalnoe Raspredalenie Turkestankie Jevotnie’ (Moscow, 1873). 
Unfortunately both Mr. Severtzoff’s works are written in Russian, a 
Janguage which is utterly unintelligible to the larger number of Euro- 
pean and American naturalists. We feel, therefore, that no excuse is 
necessary for laying before the Society a more or less full abstract of 
all that touches the subject of this paper*. 
Almost all we know respecting the Turkestan species being con- 
tained in Severtzoff’s work, we shall, in treating of these species, 
adhere as closely as possible to Mr. Severtzoff’s own words. At the 
end of the account of each species we will add any observations 
which may suggest themselves to us as worthy of notice. In the 
case of the species not found in Turkestan, we shall give original 
descriptions of specimens personally examined in either British or 
Contiuental museums; and finally we shall append a table of all 
the specimens which we have examined, with their measurements, 
followed by a list containing remarks on the individual peculiarities 
of each specimen, and the name of the Museum, public or private, 
in which it may be found. 
Before describing the different species of Sheep met with by him 
in Turkestan, Mr. Severtzoff defines clearly the terms used by him 
in his descriptions of the horns of Sheep; and, although we are 
unable to agree with Mr. Severtzoff in the value which he attaches 
to the characters afforded by the horns, we fully appreciate the 
practical utility of Mr. Severtzoff’s definitions. We propose, there- 
fore, following his example, to define as exactly as possible the fea- 
tures observable in an adult typical Sheep’s horn, giving to each a 
* Mr. Severtzoff’s descriptions have been translated for us by Mr. F. Craemer. 
