Suborder Colocephali, or Morays.—In the suborder Colocephali (κολός, deficient; κεφαλή, head) the palatopterygoid arch and the membrane-bones generally are very rudimentary. The skull is thus very narrow, the gill-structures are not well developed, and in the chief family there are no pectoral fins. This group is very closely related to the Enchelycephali, from which it is probably derived.
Fig. 111.—Jaws of Nemichthys avocetta Jordan & Gilbert.
In the great family of morays (Murænidæ) the teeth are often very highly developed. The muscles are always very strong and the spines bite savagely, a live moray being often able to drive men out of a boat. The skin is thick and leathery, and the coloration is highly specialized, the pattern of color being often elaborate and brilliant. In Echidna zebra for example the body is wine-brown, with cross-stripes of golden yellow. In Muræna each nostril has a barbel. Muræna helena, the oldest moray known, is found in Europe. In Gymnothorax, the largest genus, only the anterior nostrils are thus provided. Gymnothorax mordax of California is a large food-fish, as are also the brown Gymnothorax funebris and the spotted Gymnothorax moringa in the West Indies. These and many other species may coil themselves in crevices in the reefs, whence they strike out at their prey like snakes, taking perhaps the head of a duck or the finger of a man.
In many of the morays the jaws are so curved and the mouth so filled with knife-like teeth that the jaws cannot be closed. This fact, however, renders no assistance to their prey, as the teeth are adapted for holding as well as for cutting.
In Enchelynassa bleekeri, a huge wine-colored eel of the South Seas, the teeth are larger than in any other species. Evenchelys (macrurus) is remarkable for its extraordinary length of tail, Echidna for its blunt teeth, and Scuticaria, Uropterygius, and Channomuræna for the almost complete absence of fins. In Anarchias (allardicei; knighti), the anal fin is absent. The flesh of the morays is rather agreeable in taste, but usually oily and not readily digestible, less wholesome than that of the true eels.
Fig. 112.—Muræna retifera Garman. Charleston, S. C.
The Myrocongridæ are small morays with developed pectoral fins. The species are few and little known.
Family Moringuidæ.—Structurally one of the most peculiar of the groups of eels is the small family of Moringuidæ of the East and West Indies. In these very slender, almost worm-like fishes the heart is placed very far behind the gills and the tail is very short. The fins are very little developed, and some forms, as Gordiichthys irretitus of the Gulf of Mexico, the body as slender as a whiplash, possess a very great number of vertebræ. Moringua hawaiiensis occurs in Hawaii, M. edwardsi in the Bahamas. This family probably belongs with the morays to the group of Colocephali, although its real relationships are not wholly certain.