effective in the production of the several British breeds. As soon as two
or more breeds were formed in any district, or when new breeds descended
from distinct species were introduced, their crossing, especially if aided
by some selection, will have multiplied the number and modified the
characters of the older breeds.

SHEEP.

I shall treat this subject briefly. Most authors look at our domestic sheep
as descended from several distinct species. Mr. Blyth, who has carefully
attended to the subject, believes that fourteen wild species now exist, but
"that not one of them can be identified as the progenitor of any one of the
interminable domestic races." M. Gervais thinks that there are six species
of Ovis (3/73. Blyth on the genus Ovis in 'Annals and Mag. of Nat. History'
volume 7 1841 page 261. With respect to the parentage of the breeds see Mr.
Blyth's excellent articles in 'Land and Water' 1867 pages 134, 156. Gervais
'Hist. Nat. des Mammiferes' 1855 tome 2 page 191.) but that our domestic
sheep form a distinct genus, now completely extinct. A German naturalist
(3/74. Dr. L. Fitzinger 'Ueber die Racen des Zahmen Schafes' 1860 s. 86.)
believes that our sheep descend from ten aboriginally distinct species, of
which only one is still living in a wild state! Another ingenious observer
(3/75. J. Anderson 'Recreations in Agriculture and Natural History' volume
2 page 264.), though not a naturalist, with a bold defiance of everything
known on geographical distribution, infers that the sheep of Great Britain
alone are the descendants of eleven endemic British forms! Under such a
hopeless state of doubt it would be useless for my purpose to give a
detailed account of the several breeds; but a few remarks may be added.

Sheep have been domesticated from a very ancient period. Rutimeyer (3/76.
'Pfahlbauten' s. 127, 193.) found in the Swiss lake-dwellings the remains