ae HAPLOMI 617 
line. The teeth vary much in shape: cardiform, villiform, or 
compressed, and bi- or tri-cuspid ; the palate is either toothless, or 
teeth are present on the vomer. About 200 species are known, 
mostly from the American continent, only about 30 being known 
from other parts of the world, viz. Southern Europe, Southern Asia 
and Japan, and Africa. In many species the sexes are dissimilar, 
the female being larger and less brilliantly coloured, with smaller 
fins; the anal fin of the male may be modified into an intro- 
mittent organ by means of which internal fertilisation takes place, 
the ova developing in a sort of uterus, which the young leave in 
a more or less advanced stage of growth. The most curious of 
Fig. 374.—Anableps tetrophthalmus, male, 4 nat. size. 
the Cyprinodontids is the genus Anableps, of Central and South 
America, surface-swimming Fishes, the strongly projecting eyes of 
which are divided by a horizontal band of the conjunctiva into an 
upper part adapted for vision in the air, and a lower for vision in 
the water, and the pupil is divided into two parts by a constriction; 
the larger species grows to the length of a foot. 
Fic, 375,—Distribution of the Cyprinodontidae. 
