NO. 4 MYERS AND WADE : NEW GENERA AND SPECIES OF EELS 81 



Genus LETHARCHUS Goode and Bean 



Letharchus Goode and Bean, 1882, Proc. U.S. Nat. Mus., vol. 5, p. 436 

 (type by monotypy L. velifer Goode and Bean). 



Dorsal fin inserted slightly behind eye; the fin high until above the 

 middle of tail, becoming obsolete toward end. Anal and pectoral fins 

 entirely absent. Mouth and cranial parts of the head very small for an 

 Ophichthyid, the mouth inferior. Gill openings curved, the posterior part 

 of each nearly horizontal. A deep pocket, like a second (anterior) open- 

 ing, in front of each gill opening. Directly below the gill openings a deep, 

 transverse groove (indistinct in poorly preserved specimens) crosses the 

 isthmus. From this groove, two folds of skin extend backward on each 

 side of the under part of the body, fading out somewhere between the 

 middle of the trunk and the anal opening; between the folds the belly is 

 flat. 



Gular region swollen, the exterior of the lower part thrown into 

 several longitudinal folds in well-preserved specimens, these folds ending 

 abruptly at the transverse groove across the isthmus. Jugostegalia well 

 developed. Anterior nostrils with an incipient or well-developed tube ; the 

 end of tube with three papillae, one anterior and two lateral (the lateral 

 larger), which project into the opening and tend to close the nostril. 

 Posterior nostrils under lip and beneath eye, more or less slitlike and 

 marked externally by a dermal flap beneath the eye. Lateral line con- 

 spicuous. 



Three species known, one from the coast of the South Atlantic States 

 and the Caribbean, another from Lower California, and the third, the 

 new species described below. The above description was made from an 

 examination of a specimen of L. velifer (Stanford 3932), from Charles- 

 ton, South Carolina, and the types of L. opercularis. 



Key to the Known Species 



la. Anterior nostrils scarcely tubular; lower jaw much longer than 

 its width from rictus to rictus; pupil ovate, the iris dark except for 

 a light inferior elliptical or top-shaped area (which includes the 

 pupil) ; middle of pupil far anterior to the mj'ddle of the length of 

 the lower jaw; body deep uniform brown; the dorsal fin white with 

 a dark margin (Atlantic) L. t/e'/f/^r Goode and Bean. 



