se it, are not
sufficiently numerous to enable the naturalist to divide them into
sub-genera. This is abundantly proved by the unsuccessful result of
those attempts which have already been made to arrange them into minor
groups. Nor can we wonder at this want of success, when we consider that
even many of the species usually regarded as distinct are by no means
clearly defined.

The second object, therefore, of this treatise, is (by bringing into
juxta-position all the most important facts concerning the various
individual specimens which have been described, and by adding several
other facts of importance which have not hitherto been noticed,) to
enable the naturalist to define, more correctly than has yet been done,
the peculiarities of each species.

A third object is to direct the attention of travellers more
particularly to this subject; in order that, by their exertions, our
information upon this class of animals may be rendered more complete.

A new and important feature in the present Monograph, is the
introduction of a Table of the Number of Vertebrae, carefully constructed
from an examination of the actual skeletons, by which will be seen at a
glance the principal osteological differences of species which have
hitherto been confounded with each other. A Table of the Periods of
Gestation is likewise added, which presents some equally interesting
results.

Several of the descriptions have been verified by a reference to the
living animals, seven specimens of which are at present (1847) in the
Gardens of the Zoological Society, Regent's Park. The several Museums in
the Metropolis have likewise been consulted with advantage.

I am indebted to Judge FURNAM, of the United States, for some original
information respecting the American Bison; and also to the late Mr.
COLE, who was forty years park-keeper at Chillingham, for answers to
several questions which I proposed to him on the subject of the
Chillingham Cattle.

I beg to acknowledge my obligation to Mr. CATLIN for kindly allowing me,
not only to make extracts, but also to copy some of the outlines from
his 'Letters and Notes on the North American Indians,' a work which I do
not hesitate to pronounce one of the most curious and interesting which
the present century has produced,--whether we regard the graphic merits
of its literary or pictorial department.

To Professor OWEN and the Officers of the Royal College of Surgeons, to
the Officers of the Zoologi