LYCHNOPOLES ARGENTEOLUS. 245 



as wide as the interorbital space. Mouth large, oblique, about three fourths 

 as long as the head, inidlcnglh below the eye ; maxillary short, curved on 

 the lower edge, rounded at the end, extending one diameter of the eye 

 backward of the latter ; interniaxillaries forming more than half the length 

 of the upper jaws. Teeth small, unequal, slender, sharp, hooked, in two 

 series, alternating, on intermaxillaries and dentaries, in a single series on 

 maxillaries and palatines. Six teeth on each palatine. None of the teeth 

 are large enough to be called fangs ; the inner are opposed to the spaces 

 between the outer on each jaw ; the maxillary teeth are somewhat inclined 

 forward. Gills four; no psoudobranchia3 ; gill rakers slender, as long as 

 the eye ; six plus fourteen on the outer edge of the first arch. Opercles 

 very thin. Scales large, broad, thin, deciduous ; cheek scales moderately 

 large, very thin, the large one on the maxillary as long as the eye and half 

 as wide. Vent midway from the snout to the end of the caudal, below the 

 fourth ray of the dorsal fin. Seven pyloric ca^ca. A short, sliprp, spine- 

 like angle below the isthmus. 



Dorsal origin midway from the eye to the base of the caudal ; base of 

 dorsal ending above the eleventh ray of the anal. Anal origin below the 

 sixth ray of the dorsal ; anal base twice the length of that of the dorsal. 

 Ventrals small, half Avay from the pectorals to the vent. Pectorals small, 

 low upon the sides. No adipose fin apparent. Caudal forked. 



The luminous facets are mostly in function downward. With one 

 exception, perhaps, each facet is composed of a black substructure on which 

 rests a j-ellow disk, usually at the upper edge in the organs of the sides, 

 having toward the lower edge a bluish or silvery area similar in a measure 

 to that in the facets of Argyropelecus. In the ventral series of facets on 

 each side of the body there is a single one below the snout, followed by 

 nine below the hyoid and these by fifteen from the pectorals to the ventrals, 

 plus nine from the ventrals to the vent, plus twenty-two from the vent to 

 the caudal. In the next series above the ventral there are two facets on 

 the operculum plus eleven from the shoulder to the ventrals, plus ten 

 from the ventrals to the vent, plus twenty-two from the ventrals to the 

 caudal. On the flank above the lower two rows there is a third series of 

 smaller facets and above this a fourth of hardly more than dots. The large 

 facet between the eye and the intermaxillary is peculiar in that it is hard 

 and black at the surface while the yellow matter usually forming the disk 

 lies under or behind it as if the facet was in function inward or backward. 



