lengthened, flattened sidewise, and coming to an edge along the back. They have only two or three gill-rays, which are slender. There are two dorsals, the first strongly spinous, and both placed far behind; and small ventrals situated behind the pectorals. The mouth is very small and opens obliquely; the intestinal canal has two or three folds, but no cæcal appendages; there is an air-bladder of considerable size. Ten species are comprised in this sub-family, forming two genera; they are scattered over the Atlantic and Pacific Oceans; one is common in the Mediterranean, whence it occasionally wanders to the southern shores of Great Britain.
Genus Centriscus, (Linn.)
In this genus the form is short and compressed, the depth much exceeding the transverse diameter of the body; the head is not far short of half the whole length, much produced into a slender tube; the mouth, opening at the extremity, is very small, and destitute of teeth. The first dorsal is situated far back, and contains three or four spinous rays, of which the first is large and strong, connected by intermediate pieces with the bones of the shoulder and the skull: being thus supported, and very stout and strong in itself, and armed with a series of rugged teeth along its hinder edge, this spine forms a powerful weapon of offence and defence, capable of being moved at the will of the animal. The ventral fins are small and united. The body is covered with small scales, and with some larger toothed ones over the bony apparatus that connects the
