=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. =Order Carencheli, the Long-necked Eels.=—Certain offshoots from the Apodes so widely diverging in structure that they must apparently be considered as distinct orders occur sparingly in the deep seas. One of these, _Derichthys serpentinus_, the long-necked eel, constitutes the sole known species of the suborder _Carencheli_ (καρά, head; ἔγχελυς, eel). In this group the premaxillaries and maxillaries are present as in ordinary fishes, but united by suture and soldered to the cranium. As in true eels, the shoulder-girdle is remote from the skull. The head is set on a snake-like neck. The single species representing the family _Derichthyidæ_ was found in the abysmal depths of the Gulf Stream. [Illustration: FIG. 113.—_Gymnothorax berndti_ Snyder. Hawaii. Family _Murænidæ_. ] [Illustration: FIG. 114.—_Gymnothorax jordani_ (Evermann & Marsh). Family _Murænidæ_. Puerto Rico. ] [Illustration: FIG. 115.—Moray, _Gymnothorax moringa_ Bloch. Family _Murænidæ_. Tortugas. ] [Illustration: FIG. 116.—_Derichthys serpentinus_ Gill. Gulf Stream. ] [Illustration: FIG. 117.—Gulper-eel, _Gastrostomus bairdi_ Gill & Ryder. Gulf Stream. ]