PREFACE. 4 
or very rarely a more extended meaning than its original 
proposer applied to it. If this was not allowed, many new 
names must be added to the list of genera, which is already 
so overburdened with synonyma. In those cases where the 
two sexes of the same species, or any particular individual 
state or variety belonging to it, have been differently named, 
the names belonging exclusively to the state or individual 
described are placed after the reference to the specimens to 
which they apply. To determine with accuracy the names 
and synonyma of the species, the various specimens, skele- 
tons and other remains of Hoofed animals in the Museums 
of the Zoological Society, of the East India Company, of the 
Naval Hospital at Haslar, and of the different local Societies, 
especially those of Liverpool, Bristol, &c., and the various 
continental Museums of Paris, Leyden, Berlin, Vienna, 
and Frankfort, have been personally examined, and in 
many cases the specimens contained in those Museums have 
been sent to the Museum, so that they could be actually 
compared with specimens in the Museum Collection. 
JOHN EDWARD GRAY. 
British Museum, 
lst December, 1852. 
