The body is covered with a jointed, chitinous shell, like many of the insects. This peculiarity left early naturalists in doubt as to whether it actually was a fish or some sort of monstrous water bug. It is, of course, a true fish with no insect affiliations. The hard shell makes it a feeble, inefficient swimmer. It is able, in fact, to swim at all only because of a large air bladder so delicately adjusted to the specific gravity of the animal that if a gas bubble the size of a pinhead is let out by a puncture the sea horse sinks to the bottom. There it can only crawl about clumsily until the wound is healed. Because it is so poor a swimmer the hippocampus must have other means of adjustment to its salt water environment. This is afforded by a prehensile tail which it can wrap around the stems of water plants. This kind of a tail is found among a few mammals, notably the smaller monkeys. So far as is known, no other fish has anything of the sort. The animal is most frequently observed in a state of rest, its tail wrapped around a plant and its body standing nearly erect in the water. Its food consists of tiny crustaceans and other sea organisms of like size. Because of its poor powers of locomotion, it must wait for those which come within reach of its jaws which work with lightning-like speed, or for those which will wait accommodatingly for it to come and get them. Hippocampus can move its eyes independently of each other, thus looking backward and forward at the same time. It would be rather difficult for a predaceous organism to take it by surprise, but on the other hand it would have little ability to fight back or flee if attacked. Some species, at least, have considerable ability to change color to blend with the environment. Bright red, pink or yellow specimens when caught fade rapidly to normal mottled gray. Probably the greatest anomaly of the hippocampus family is its way of reproducing the species. The male actually “gives birth” to living young. The process, so far as known, is unduplicated in nature. Unfertilized eggs are laid by the female. She places them, a few at a time, into a pouch-like organ on the underside of the male’s body. In some fashion still unknown to biologists they are fertilized in the transfer. Within this pouch the eggs are incubated and there the young remain for several days after they are hatched. Then, fully equipped to take care of themselves, they are expelled into the water. So far as has been observed, there is no further parental interest in them. This male pouch might be considered as filling the double function of the womb of a placental mammal and the pouch of a marsupial like the kangaroo.