Synaphobranchidae

Cutthroat eels
Muddy arrowtooth eel, Ilyophis brunneus. From plate 43 of Oceanic Ichthyology by George Brown Goode and Tarleton Hoffman Bean, published 1896.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Superorder:	Elopomorpha
Order:	Anguilliformes
Family:	Synaphobranchidae J. Y. Johnson, 1862
Genera
Atractodenchelys Diastobranchus Dysomma Dysommina Haptenchelys Histiobranchus Ilyophis Linkenchelys Meadia Simenchelys Synaphobranchus Thermobiotes

Cutthroat eels are a family, Synaphobranchidae, of eels, the only members of the suborder Synaphobranchoidei. They are found worldwide in temperate and tropical seas.

Cutthroat eels range from 23 to 160 cm (9.1 to 63.0 in) in length. They are bottom-dwelling fish, found in deep waters down to about 3,700 m (12,100 ft). They are distinguished by the presence of telescopic eyes in the larvae. In some classifications (for example, ITIS), this family is split, with Simenchelys in its own family, the Simenchelyidae.

...
Wikipedia