MYCTOPHUM AUROLATERNATUM. 265 
as the eye, narrower than deep, bluntly rounded in front, internarial keel 
on the skull low. Eye large, twice as long as the snout, one and one fourth 
times as wide as the interorbital space, nearly one third of the length of the 
head; orbit not cutting into the upper profile. Mouth wide, reaching more 
than halfway from the snout to the base of the pectoral, about twice as long 
as the eye; maxillary reaching backward of the orbit one half the ocular 
diameter. Teeth small, in narrow villiform bands on intermaxillaries, denta- 
ries, and palatines, and ina small group at each side of the vomer. Gill 
openings wide; membranes hardly united, free from the isthmus. Gill 
‘ukers more than half as long as the eye, slender, compressed, five plus thir- 
teen. Preopercular ridge low, no spine at its junction with the postorbital 
ridge. Scales large, larger on the lateral line, three above the line and four 
below it, seven to nine from the adipose fin to the caudal. 
Third ray of the dorsal fin midway from the snout to the base of the 
caudal ; basal length less than one and one half times the length of the eye, 
base above the middle of the space between the ventrals and the anal. Adi- 
pose fin distant from the base of the first dorsal one and one half lengths of 
the latter, or from the base of the caudal one length of the dorsal base which 
is half the length of the head. Ventral base slightly in advance of the verti- 
cal from the first ray of the dorsal. Anal origin little backward of the last 
ray of the dorsal; anterior two rays and all those behind the middle of the fin 
short; hindmost three rays below the adipose fin. Caudal deeply forked. 
The arrangement of the lanterns, light organs, light facets, etc., does not 
differ very much from that seen’ on Myctophum Cuninianum. There are 
three to four facets in the mandibular and branchiostegal series; a small 
one lies at the end of the mouth cleft and a larger one above it at the end 
of the maxillary; one lies on the base of the pectoral, above and forward of 
it at the edge of the operculum halfway to the lateral line another, and 
below and forward half way to the ventral series a third; one lies at the 
origin of the ventral and above it midway to the lateral line another; above 
the vent there is a series of three, the uppermost a little below the line, and 
behind this upper one halfway to the base of the caudal, close to the line, 
there is a single one; in the ventral series there are four from the isthmus 
to the ventrals, four from the ventrals to the anal, ten along the base of the 
anal fin, six below each side of the caudal pedicel, and two at the base of 
the caudal. Three considerable spaces separate the groups backward of the 
vent, the lanterns being quite close together in each group. 
