4 LLOYD'S NATURAL HISTORY, 
Gnus of Africa, On the other hand, white transverse stripes on 
a tawny or chestnut ground are common among Antelopes, 
whereas they are quite unknown in the Cats. And whereas in 
the latter group dark spots on a light ground are prevalent, in 
the former just the reverse of this arrangement holds gocd. 
That there is some sufficient reason for this prevalence of one 
type of coloration in one group of animals, and its replace- 
ment by another in a second, may be taken for granted, 
although at present naturalists have not succeeded in unravel- 
ling the mystery in which the subject is enveloped. 
The Cats, under which title are included Lions, Tigers, Leo. 
pards, Pumas, Tiger-Cats, Domestic Cats, and Lynxes, form a 
well-marked family group of the Terrestrial Carnivora, readily 
distinguished from most of their allies, with the exception of 
the Fossa (Cryptoprocta) of Madagascar, by which they appear 
closely connected with the Civets (Viverride). In this work we 
must take it for granted that the reader is more or less in- 
timately acquainted with the distinctive structural features of 
the Carnivora—a group which, in addition to the more typical 
terrestrial forms, is likewise taken to include the aquatic Seals 
and Walruses. It may be mentioned here, however, that the 
Terrestrial Carnivora, among which the Otters and Sea-Otters 
are included, are specially characterised by the special develop- 
ment of a pair of teeth in each jaw to bite against one another 
with a more or less marked “‘scissor ”-like action ; although the 
peculiar features of these teeth are less conspicuously marked in 
the Bears and Racoons than in the majority of the other mem- 
bers of the group. Not the least remarkable feature connected 
with these teeth, which, as already mentioned, are termed car- 
nassials or sectorials, is the circumstance that the upper pair do 
not correspond serially with those of the lower jaw. That is to 
say, that while in the upper jaw this pair of teeth belong to the 
pre-molar series, or those preceded by milk- or baby-teeth, 
