Sea Cat, the common name of the cartilaginous fishes of the order holocephala and family chimoeroidei. They seem to form a group intermediate between the sturgeons and sharks; the dorsal cord is continuous, with cartilaginous neural arches and transverse processes; the skull is short and rounded, produced on each side into a process to which the lower jaw is connected instead of to an os quadratum; the upper jaw and palate are fused with the skull, without traces of suture; the upper jaw has four broad plates or teeth, and the lower two; the eyes very large and without lids; nasal cavities very large and convoluted, opening on the under side of the snout in front of the mouth, which is small; the branchiae are not fixed by their outer margin, and are covered by a small operculum, adhering to the hyoid arch, with only a single aperture on each side behind the head, communicating interiorly with five branchial sacs opening separately into the pharynx; there is no air bladder, and the intestine has a spiral valve.

The skin is covered with placoid granules; between the eyes is a fleshy club-shaped process, with serrated edge and ending in a spine, which somewhat resembles a crown, and has given rise to one of its popular names, "the king of the herrings." The ventrals are abdominal, the anal small, the pectorals powerful, and the tail heterocercal; the anterior dorsal is short, triangular, with a strong spine for the first ray, and is placed over the pectorals. They are oviparous, the large eggs being enclosed in a leathery capsule; the males have trifid claspers. - The northern sea cat (chimoera monstrosa, Linn.) has a conical snout, the dorsals contiguous and reaching to the end of the tail, which is prolonged into a slender filament; the body is elongated and shark-like; the eyes have a greenish pupil surrounded by a white iris, and they shine, especially at night, like cats' eyes, whence the common name; the color is silvery with brown spots; the tail is nearly as long as the body. It attains a length of 3 or 4 ft., and is found in the North sea and northern Atlantic, where it pursues the shoals of herring and other migratory fish; it also feeds on jelly fishes and crustaceans.

The flesh is tough, but the Norwegians use the eggs as food, and employ the oil of the liver in diseases of the eyes and for wounds. - In the southern sea cat (callorhynchus australis, Gronov.) the snout ends in a gristly appendage, bent backward at the end so as to resemble a hoe; the anterior dorsal is very far forward over the pectorals, the second over the ventrals and reaching to the caudal, and the tail does not end in a filament. It is of about the same size as the northern animal, and silvery, tinged with yellowish brown.

Northern Sea Cat (Chimaera monstrosa).

Northern Sea Cat (Chimaera monstrosa).