STICKLEBACK, a small fish of the fam ily Gosterosteide, order Hentibranchii,in which the rays of the first dorsal fin form a series of detached spines. The body is elongated and compressed and tapers behind to a narrow caudal peduncle. Teeth exist in both jaws, but are absent from the tongue and palate. The premaxillary is protractile. The sides of the body may be covered with vertical bony plates, while the other parts are destitute of any scaly covering. These fishes inhabit the rivers and brackish waters of temperate climates of the northern hemisphere. The brook stickleback (G. bispinosus), very common on the New Eng land and New Jersey coasts and sometimes in fresh water, is a voracious little fish, swimming eagerly after bait of all kinds, and not at all disturbed by noises and acts which would in fallibly frighten away most other fishes. It is highly pugnacious, especially at the breeding season. In its reproductive habits it evinces many most interesting features, constructing a nest and attending its young with care and affection. The nest is the size of a large hick
ory-nut and is composed of vegetable matters, pieces of straw, sticks and the like, bound to gether with a silky fibre secreted by an organ closely connected with the kidneys of the male. In the top of the nest a small pit is formed in which the eggs are deposited. These are about the size of .poppy seeds, and are bright-yellow. Over this nest and its contained ova the fishes watch with the most jealous care, the male tak ing upon himself almost the entire duty of nidi fication, as well as of tending the young after hatching. The genera Eucalia, Pygosteus and Apeltes are all represented in the salt or fresh waters of the United States, where are found seven species of these interesting little fishes, each exhibiting individual peculiarities in ap pearance and habits. Consult Gill, (Standard Natural History,) Vol. III (Boston 1885), and Ryder, (Bulletin United States Fish Commis sion) (Washington 1881).