592 Bulletin 47, United States National Museum. 



behind the eye there is a luminous body, which is nearly as long as the 

 eye aud somewhat club-shaped ; at margin of operculum there is a small, 

 roundish, luminous dot. Maxillary a very thin and narrow bone, extend- 

 ing backward ahnost to the end of the head, very slightly curved and 

 forming a very obtuse angle with the short premaxillary ; mandible very 

 strongly curved upward, like a sled runner, its length twice greatest 

 hei"-ht of body. Both jaws armed with numerous fine teeth of unequal 

 size; only 3 remain on each side of the premaxillary; maxillary with 20 

 true teeth on its anterior half, the posterior half with about 16 serne ; 

 about 35 teeth on each side of mandible ; all the teeth of jaws rake inward 

 and backward, and are depressible ; 3 teeth on each side of the head or 

 the vomer, increasing in size backward ; a pair of teeth on each i)alatine; 

 1 fang near the tip of the tongue and 3 farther back. Gill laminje not 

 well covered by the operculum; gill rakers very few, minute and spine- 

 like ; gill opening very w^de, the membrane cleft almost down to origin 

 of hyoid barbel. No pseudobrauchiie. Hyoid barbel situated nearly 

 under tip of tongue, evidently imperfect, its length scarcely \ tliat of eye. 

 Longest dorsal ray a little longer than eye; anal beginning immediately 

 under the dorsal, its base slightly longer than that of dorsal, its rays 

 about as long as those of dorsal ; distance of ventral from tip of 

 snout a little more than I body; origiu of ventral very slightly nearer 

 root of caudal than tip of snout ; pectoral wanting. Color very dark ; 

 a row of luminous dots along margin of branchiostegal membrane; 

 two rows beginning on the isthmus and extending back along edge of 

 belly, passing between ventrals and slightly above base of anal, disap- 

 pearing rear end of body ; another row higher up on side, which can 

 not be traced back farther than the ventral, on account of the bad con- 

 dition of the specimen. Only the type known. Length 7 inches. (Goode 

 &L Bean.) {(jracilis, slender.) 



Photonecten gracilis, Goode & Bean, Oceanic UlithyoUigy, 112, flg. 137, 1895, off Martinique, at 

 Blake Station XL, in 472 fathoms. (Cull. Str. Blake.) 



Family LXXX. MALACOSTEID^. 



Body elongate, compressed, scaleless. Mouth immense. Snout very 

 short. Cleft of the mouth exceedingly wide, the ends of the jaws extend- 

 ing beyond the root of the pectorals, and the jaws not connected with 

 the sides of the head back of the orbit. Tail diphycercal. Lateral mar- 

 gins of the upper jaw formed by the premaxillaries only. No adipose fin ; 

 pectorals rudimentary. No barbel, but a strap-shaped elastic band con- 

 ■ nectiug the symphysis of lower jaw with the isthmus. (Goode A: Bean.) 

 Deep sea. Two species known ; among the most remarkable known 

 forms. 



283. MALACOSTEUS, Ayres. 



Malacosleus, Ayres, Journ. Bost. Sec. Nat. Hist., 1849, 53, {mger). 



Body elongate, compressed, scaleless, deepest at the head and tapering 

 backward. Head rather compressed, the snout extremely short ; jaw 

 bones and preopercles greatly jnolonged, forming an enormous gape, 

 extending to behind the root of the pectorals aud large enough to permit 



