Families of Nematognathi.—According to Dr. Eigenmann's scheme of classification,[[11]] the most primitive family of Nematognathi is that of Diplomystidæ, characterized by the presence of a well-developed maxillary, as in other soft-rayed fishes. The single species, Diplomystes papillosus, is found in the waters of Chile.
[11]. A Revision of the South American Nematognathi, 1890, p. 7.
Similar to the Diplomystidæ in all other respects is the great central family of Siluridæ, by far the most numerous and important of all the divisions of Nematognathi.
The Siluridæ.—This group has the skin naked or imperfectly mailed, the barbels on the head well developed, the dorsal short, inserted forward, the adipose fin without spine, and the lower pharyngeals separate. All the marine catfishes and most of the fresh-water species belong to this group, and its members, some 700 species, abound in all parts of the world where catfishes are known—"a bloodthirsty and bullying race of rangers inhabiting the river bottoms with ever a lance at rest and ready to do battle with their nearest neighbor."
The Sea Catfish.—In the tropical seas are numerous species of catfishes belonging to Tachysurus, Arius, Galeichthys, Felichthys, and other related genera. These are sleek, silvery fishes covered with smooth skin, the head usually with a coat of mail, pierced by a central fontanelle. Some of them reach a considerable size, swarming in sandy bays. None are valued as food, being always tough and coarsely flavored. Sea birds, as the pelican, which devour these catfishes are often destroyed by the sudden erection of the pectoral spines. None of these are found in Europe or in Japan. Of the very many American species the gaff-topsail catfish (Felichthys felis), noted for its very high spines, extends farthest north and is one of the very largest species. This genus has two barbels at the chin. Most others have four. The commonest sea catfish of the Carolina coast is Galeichthys milberti. In Tachysurus the teeth on the palate are rounded, in most of the others they are in villiform bands.
Fig. 141.—Gaff-topsail Cat, Felichthys felis (L.). Wood's Hole.
Fig. 142.—Sea Catfish, Galeichthys milberti (Cuv. & Val.). Pensacola.
In most or all of the sea catfish the eggs, as large as small peas, are taken into the mouth of the male and there cared for until hatched.