1841.] A Monograph of the species of Wild Sheep. 861 



a third. When upon the head, it must accordingly have gyred consi- 

 derably inward, instead of descending at a parallel with the other, as 

 indeed is almost invariably the case with the domestic O. Aries, Both 

 specimens are of a pale colour, and indented with rugged transverse 

 strise, in general half an inch apart. Considering, indeed, the differ- 

 ences of the two specimens, it is by no means improbable that they will 

 prove to be of allied rather than of the same species, in which case 

 my former name of O, Sculptorum might be retained for that to which 

 it was applied. 



2, 3, and 4. — The Museums of Western Europe do not, that 

 I can learn, contain any portion of the Siberian Argali, Ovis Ammon 

 of Pallas, that might serve for comparison with the Rocky Moun- 

 tain Sheep of North America, O. montana of Desmarest ; but as 

 the Kamtschatka Argali is described as a distinct species, O. nivicolaj 

 by M. Eschscholtz, in his Zoologischer Atlas, (differing from the two 

 preceding in its inferior size, and in wanting, it would appear, the 

 pale disk surrounding the tail, so conspicuous in both the others,) the 

 probability is thus enhanced, that the Siberian and Rocky Mountain 

 species are not the same, however closely they may resemble. The 

 descriptions of O. Ammon would seem to apply in every particular to 

 the O, montana, though it is still probable that actual comparison of 

 specimens would lead to the detection of some discrepancies, as 

 generally, but not always, happens in like cases. I may notice, 

 that while Mr. Drummond affirms that the horns of old rams 

 of O. montana " attain a size so enormous, and curve so much 

 forwards and downwards, that they effectually prevent the animal 

 from feeding on level ground," the same had previously been remark- 

 ed by Strahlenberg of the Argalis of Siberia, and no doubt is equally 

 observable in the Rasse of Pamir. The finest specimen of a head of 

 the Rocky Mountain animal, of seven heads of adult males ex- 

 amined, is in the collection of this (the Zoological) Society, and 

 gives the following admeasurements ; horns 3 feet 5 inches over 

 the front ridge, and 17 j inches round at base, where the front angles 

 are 4| inches apart. They number nine years of growth, which 

 successively give 9, 7^, 6^, 5, 41 4, 2i, 1;^, and 1 inches. They are 

 nearly equilaterally triangular, but bulge a little between the angles, 



having the inner or front angle obtusely prominent, the posterior 



5 R 



