Fig 107.—Xyrias revulsus Jordan & Snyder. Family Ophichthyidæ. Misaki, Japan.
In the genus Sphagebranchus, very slender eels of the reefs, the fins are almost wanting.
Fig. 108.—Myrichthys pantostigmius Jordan & McGregor. Clarion Island.
Fig. 109.—Ophichthus ocellatus (Le Sueur). Pensacola.
Allied to the Congers is the small family of duck-billed eels (Nettastomidæ) inhabiting moderate depths of the sea. Nettastoma bolcense occurs in the Eocene of Monte Bolca. The produced snout forms a transition to the really extraordinary type of thread-eels or snipe-eels (Nemichthyidæ), of which numerous genera and species live in the oceanic depths. In Nemichthys the long, very slender, needle-like jaws are each curved backward so that the mouth cannot by any possibility be shut. The body is excessively slender and the fish swims with swift undulations, often near the surface, and when seen is usually taken for a snake. The best-known species is Nemichthys scolopaceus of the Atlantic and Pacific. Nemichthys avocetta, very much like it, has been twice taken in Puget Sound.
Fig. 110.—Thread-eel, Nemichthys avocetta Jordan & Gilbert. Vancouver Island.