268 
THE PRINCIPLES OF 
Part II. 
respects, that the males when caught are valued at 
twenty per cent, above the females . 7 With other pachy- 
dermatous animals the sexes differ very little or not at 
all, and they are not, as far as known, polygamists. 
Hardly a single species amongst the Cheiroptera and 
Edentata, or in the great Orders of the Rodents and 
Insectivora, presents well-developed secondary sexual 
differences ; and I can find no account of any species 
being polygamous, excepting, perhaps, the common rat, 
the males of which, as some rat-catchers affirm, live 
with several females. 
The lion in South Africa, as I hear from Sir Andrew 
Smith, sometimes lives with a single female, but gene- 
rally with more than one, and, in one case, was found 
with as many as five females, so that he is polygamous. 
He is, as far as I can discover, the sole polygamist in 
the whole group of the terrestrial Carnivora, and he 
alone presents well-marked sexual characters. If, how- 
ever, we turn to the marine Carnivora, the case is widely 
different ; for many species of seals offer, as we shall 
hereafter see, extraordinary sexual differences, and they 
are eminently polygamous. Thus the male sea-ele- 
phant of the Southern Ocean, always possesses, accord- 
ing to Pdron, several females, and the sea-lion of Forster 
is said to be surrounded by from twenty to thirty females. 
In the North, the male sea-bear of Steller is accom- 
panied by even a greater number of females. 
With respect to birds, many species, the sexes of 
which differ greatly from each other, are certainly 
monogamous. In Great Britain we see well-marked 
sexual differences in, for instance, the wild-duck which 
pairs with a single female, with the common blackbird, 
7 Dr. Campbell, in ‘ Proc. Zoolog. Soc.’ 1869, p. 138. See also an 
interesting paper, by Lieut. Johnstone, in ‘ Proc. Asiatic Soc. of Bengal,’ 
May, 1868. 
