Chap. XII. 
FISHES. 
7 
strong and voracious fishes, we may suspect that the 
males require their sharp teeth for fighting with their 
rivals ; but as they possess many parts modified and 
adapted for the prehension of the female, it is possible 
that their teeth may be used for this purpose. 
In regard to size, M. Carbonuier 10 maintains that 
with almost all fishes the female is larger than the male ; 
and Dr. Gunther does not know of a single instance 
in which the male is actually larger than the female. 
itli some Cyprinodonts the male is not even half as 
large as the female. As with many kinds of fishes the 
males habitually fight together ; it is surprising that 
they have not generally become through the etiects of 
sexual selection larger and stronger than the females. 
The males suffer from their small size, for according to 
I'd • Carbonuier they are liable to be devoured by the 
females of their own species when carnivorous, and no 
doubt by other species. Increased size must be in 
some manner of more importance to the females, than 
strength and size are to the males for fighting with 
other males ; and this perhaps is to allow of the pro- 
duction of a vast number of ova. 
In many species the male alone is ornamented with 
bright colours ; or these are much brighter in the male 
than the female. The male, also, is sometimes provided 
with appendages which appear to be of no more use to 
him for the ordinary purposes of life than are the tail- 
feathers to the peacock. I am indebted for most of the 
following facts to the great kindness of Dr. Gunther. 
I here is reason to suspect that many tropical fishes 
differ sexually in colour and structure ; and there are 
some striking cases with our British fishes. The male 
Qallionymus lyra has been called the gemrneous dragonet 
10 As quoted in ‘ The Farmer,’ X86S, p. 3G9. 
