Halieutæa.—Head exceedingly large, depressed, nearly circular in its circumference. Cleft of the mouth wide, horizontal. Jaws with small rasp-like teeth; palate smooth. Forehead with a transverse bony bridge, beneath which is a tentacle (rostral spine) retractile into a cavity. Body and head covered with small stellate spines. Soft dorsal and anal very short. Gill-opening superiorly in the axil; gills two and a half.
A coast-fish (H. stellata) from China and Japan. Frequently found dry in Chinese insect-boxes.
This genus appears to be represented in the Atlantic Ocean by Halieutichthys from Cuba, and by Dibranchus, dredged at a depth of 360 fathoms off the coast of West Africa; the latter genus possesses two gills only. Another genus, covered with large scattered tubercles, Aegæonichthys, has recently been described from New Zealand.
Thirteenth Family—Cottidæ.
Form of the body oblong, sub-cylindrical. Cleft of the mouth lateral. Dentition feeble, generally in villiform bands. Some bones of the head are armed; and a bony stay connects the præopercular spine with the infraorbital ring. Two dorsal fins (rarely one), the spinous being less developed than the soft and than the anal. Ventrals thoracic, with five or less soft rays.
The fishes of this family are of small size, bad swimmers, and generally living on the bottom, near the coasts, of almost all the arctic, temperate, and tropical seas. Only a few live in fresh water. They prefer shallow to deep water; and there is only one instance known of a member of this family living at a great depth, viz. Cottus bathybius from the Japanese sea, which is stated to have been dredged in a depth of 565 fathoms. Fossil representatives are few in number: two or three species of Trigla; others, although having a general resemblance to the genus Cottus, were covered with ctenoid scales, and therefore are referred to a distinct genus, Lepidocottus; they are from tertiary formations.
Cottus.—Head broad, depressed, rounded in front; body sub-cylindrical, compressed posteriorly. Scaleless; lateral line present. Pectoral rounded, with some or all the rays simple. Jaws and vomer with villiform teeth; palatine teeth none.
The “Bull-heads” or “Miller’s Thumbs” are small fishes from the shores and fresh waters of the northern temperate zone. Some forty species are known; the greater number live in the northern half of the temperate zone. On the shore, as well as in rivers, they prefer rocky or stony to muddy ground, lying concealed between the stones, and watching for their prey, which consists of small crustaceans and other aquatic animals. The common British Miller’s Thumb (C. gobio) is found in almost all suitable fresh waters of Northern and Central Europe, especially in small streams, and extends into Northern Asia. Other freshwater species abound in North America and Northern Asia. Cottus scorpius and C. bubalis, the common European marine species, range across the Atlantic to the American coasts. The male is said to construct a nest, for the reception of the spawn, of seaweeds and stones, and to anxiously watch and defend his offspring. The spine at the angle of the præoperculum, which is simple in the majority of the freshwater species, is frequently armed with accessory processes, and antler-like, in marine.
Cantridermichthys differs from Cottus in having teeth on the palatine bones.
Eleven species are known, distributed like Cottus, but absent in Europe and North-western Asia.