592 Bulletin 47, United States National Museum. 



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

 eye and somewhat club-shaped ; at margin of operculurn there is a small, 

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

 ing backward almost 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 

 height 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 serra? ; 

 about 35 teeth on ea.ch side of mandible ; all the teeth of jaws rake inward 

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

 the vomer, increasing in size backward ; a pair of teeth on each palatine; 

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

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

 like ; gill opening very wide, the membrane cleft almost down to origin 

 of hyoid barbel. No pseudobranchi*. Hyoid barbel situated nearly 

 under tip of tongue, evidently imperfect, its length scarcely ithat 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 \ body; origin 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 veutrals 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 

 & Bean.) (gracilis, slender.) 



Photonectes gracilis, GOODE & BEAN, Oceanic Ichthyology, 112, fig. 137, 1895, off Martinique, at 

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



Family LXXX. MALACOSTEID^E. 



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- 

 necting the symphysis of lower jaw with the isthmus. (Goode & Bean.) 

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

 forms. 



283. MALACOSTEUS, Ayres. 



Malacosleus, AYRES, Journ. Bost. Soc. Nat. Hist., 1849, 53, (niger). 



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

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

 bones and preopercles greatly prolonged, forming an enormous gape, 

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



