both sexes are provided with broad, flat teeth like those of the young,
and like those of the mature females of the above-mentioned species.
(10. See Yarrell s account of the rays in his History of British
Fishes, vol. ii. 1836, p. 416, with an excellent figure, and pp. 422,
432.) As the rays are bold, strong and voracious fish, 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. Carbonnier (11. As quoted in The Farmer, 1868,
p. 369.) maintains that the female of almost all fishes 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. With some Cyprinodonts the
male is not even half as large. As in many kinds of fishes the males
habitually fight together, it is surprising that they have not
generally become larger and stronger than the females through the
effects of sexual selection. The males suffer from their small size,
for according to M. Carbonnier, 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 production of a vast
number of ova.
[Fig. 29. Callionymus lyra. Upper figure, male; lower figure, female.
N.B. The lower figure is more reduced than the upper.]
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
kindness of Dr. Gunther. There 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 Callionymus lyra has
been called the gemmeous dragonet from its brilliant gem-like
colours. When fresh caught from the sea the body is yellow of various
shades, striped and spotted with vivid blue on the head; the dorsal
fins are pale brown with dark longitudinal bands; the ventral, caudal,
365