In the tropical regions of America and Africa there is found a strange "fish," about three feet long, and called the lepidosiren (Fig. 10)—scaly siren, as the name implies. In its general aspect it is decidedly reptilian, and some writers have described it under the reptiles. Nor is it strange that naturalists should have been in doubt in regard to its true affinities, for it is decidedly reptilian in appearance, and is so unlike the typical fishes in structure that it has both gills and lungs—thus leading a sort of double life. It is believed that in important respects this fish is like some of the fishes that lived in the old Devonian times.
The gar-pikes, too, depart considerably from ordinary fishes, especially in their teeth, hard, shining scales, and heterocercal tail (Fig. 11).
And the sturgeons (Fig. 12), ballasted and protected with rows of large bony plates, and with a nose fitted for "rooting," and a mouth
for sucking, and a tail more or less like that of a shark, are very unlike anything we should select as a typical fish.
And what shall we say of the "sea-horses," or hippocamps (Fig. 13), whose head reminds us far more of the head of a horse than it
Fig. 13.—Sea-Horse (Hippocampus Hudsonius, Dekay).
Fig. 14.—Pipe-fish (Sygnathus Peckianus, Storer).
does of that of a typical fish? And of the pipe-fishes (Fig. 14), or sygnathi, whose body is all length, nearly, and whose mouth is just at the extremity of a long snout; and which have this strange habit.