532 Bulletin 47, United States National Museum. 



M. Maxillaries forming lateral margin of upper jaw; barbel free at tip. 



o. Adipose fin present; pectorals present; body naked; dorsal behind 

 vent, but in advance of anal. ASTRONESTHIDJE, LXXVIII. 



oo. Adipose fin absent; pectorals present or abseut. STOMIATID^E, LXXIX. 

 nn. Maxillaries not forming part of margin of upper jaw; pectorals rudi- 

 mentary; opercles membranaceous; body scaleless; dorsal short, post- 

 median; barbel of peculiar form, connecting throat with symphysis 

 of lower jaw. MALACOSTEIDJE, i-xxx. 



jj. Photophores minute or wanting; no barbel. 



p. Premaxillaries forming margin of upper jaw; fang-like teeth in mandibles 



and palatines and sometimes on vomer. 



q. Dorsal long, occupying entire back; body naked. ALEPISAURIDJK, LXXXI. 

 qq. Dorsal short, median or posterior. 



r. Body naked. ODONTOSTOMIDA:, LXXXII. 



rr. Body covered with thin, caducous scales. PARALEPIDID.<F., LXXXIII. 

 ti. Vertebral or neural spines projecting through skin of the back in front of dorsal fin. 

 s. Body short and deep, compressed; anterior neural spines abnormally developed, 

 projecting through the skin of the back, in advance of the dorsal; pectorals 

 present; photophores present; mouth obliquely cleft or subvertical. 



STERNOPTYCHID;E, LXXXIV. 



ss. Body elongate, snake-like; vertebrae with spiny processes anteriorly which pro- 

 ject through the skin of the back in front of dorsal rays; pectorals absent; 

 body naked; dorsal long and low, beginning in advance of the vent. 



IDIACANTHIDJE, LXXXV. 



Family LXVIII. SYNODONTID^. 



(THE LIZARD FISHES.) 



Body oblong or elongate, little compressed, covered with cycloid scales, 

 rarely naked. Mouth very wide, the entire margin of the upper jaw 

 formed by the long and slender premaxillaries, closely adherent to which 

 are the slender maxillaries, the latter mostly rudimental or obsolete, 

 never widened at tip. Teeth mostly cardiform on both jaws, tongue, 

 and palatines ; canines rarely present ; large teeth usually depressible. 

 No barbels. Opercular bones usually thin, but complete. Gill mem- 

 branes separate, free from the isthmus. Branchiostegals usually numer- 

 ous. Pseudobranchise present. Gill rakers tubercular or obsolete. 

 Lateral line present. Adipose fin present, rarely obsolete; dorsal fin 

 short, of soft rays only; pectorals and ventrals present ; anal fin moder- 

 ate or long ; caudal forked. Skeleton rather well ossified. Air bladder 

 small or wanting. Intestinal canal short. Sides sometimes with phos- 

 phorescent spots or photophores. Eggs inclosed in the sacs of the ovary 

 and extruded through an oviduct. Genera about 10, species about 40, 

 mostly inhabiting shore waters, some of them descending to the depths. 

 (Scopelidce,, group Saurina, part, Giinther, Cat., v, 393-403, 1864.) 

 a. Scales present, more or less adherent. 



b. Teeth of premaxillary simple, compressed, not barbed, in one or two rows; a broad 



band of similar teeth on palate. 



c. Vent slightly nearer base of caudal than axil of pectoral; head short, blunt, 



compressed. TRACHINOCEPHALUS, 247. 



co. Vent much nearer base of caudal than base of ventrals; head depressed, with flat 



triangular snout. SYNODUS, 248. 



bb. Teeth of premaxillary in a very broad band, curved, unequal, and barbed at the end. 



a similar band on palatines. BATHYSAURUS, 249. 



oa. Scales very caducous or wanting; teeth in narrow bands; vent posterior. 



BATHYLACO, 250. 



