PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 275 
groove. A groove between the frontal bones. Orbital margins sep- 
arated by a groove from the preopercle. Margin of preopercle very 
oblique. All the membrane bones extremely thin, membranaceous. 
Hye large, 35 in head. Gill-rakers long and slender. Head 33 in length 
_ to base of caudal; depth 43. 
Head and body completely covered with thin membranaceous scales, 
those on the middle of the sides not elevated and not noticeably larger 
than the others. Free edges of all the scales crenulate, some of them, 
especially on the back, with the crenations acute, but without spines, 
the scales not being reat ctenoid or spinous. About 45 scales in a 
longitudinal series. 
A phosphorescent spot on each mandible near the symphysis, 33 pairs 
of spots along the belly, 6 in front of ventrals, 6 between ventrals and 
origin of anal, and 21 between front of anal and base of caudal. 
Caudal peduncle above and below with two or three backward-di- 
rected spines, which are apparently the exserted tips of vertebral pro- 
cesses. 
Fin rays (not quite certain, the tips being frayed out): Dorsal about 
2, anal about 16, the fins rather low. 
Origin of dorsal nearer the snout than the base of caudal, much behind 
the base of the ventrals. Ventrals short, not reaching half way to vent. 
Pectorals reaching base of ventrals. 
Color very dark steel-blue above, silvery on sides and below, with 
dark metallic luster. The usual phosphorescent spots present, as above 
described. No evident cream-colored blotch on the back of tail. | 
Myctophum crenulare is known to us at present from a single speci- 
men, about 14 inches long, taken from the stomach of an Albicore (Or- 
cynus alalonga) in Santa Barbara Channel, July 11, 1880. It had evi- 
dently just been swallowed, and is in fairly good condition. 
It belongs to that division of the genus ‘“ Scopelus” called by Dr. 
Giinther “ Myctophum” (Cat Fishes Brit. Mus., v, 405). As the latter 
name has priority over Scopelus, it must be retained as a generic name 
for some or all of these fishes. 
Table of measurements. 
TE Sq GMO) EMEA hm coma ocade SSD CCU SRO OGOnOCO UC00 Soc ceoceg Eso oe 2.20 inches 
Wenetih to base ol candali= 2-5. <5. =< seen een e an ne ome can 1.80 inches = 100 
Body: 
(Giemiosn GBMiINS 2-5 4bbc50 sce eennOeeeba64 SObchd SaShon Saeeue ceshee seoece ssc 23 
Lens Gaya Mr iginll co oer sappee sole OCobod Oss Soe DSaEeoricesecr BEEbeOOSOEOs asc 4 
Length of caudal peduncle... ... ~~ ---. seeeer eee eee ene ene nen ee eee ee eee 22 
Head: 
Greatest lem et. 1-<sse)- = = = 90 ona i ec min HO niente wien wae =nioniem cen - + == 27 
Willa @r imnilernor onl Sees pocdodanoou.catiaes cboosadc conn becoocooEcueea. 6 
Tbecpeaiin Gis Hapa re ed sa RR SE SI ee 3 ee 
enema snatiiner, ge 4). 134.5 hss dap se eee vanicko=a2-'s aves Bey ys ee 3 
Diameter of eye-......-.--.-. lig ee ees Seiten eee iae oocisin = ni wes «ir onines 8 
WO dee alesliet aa Ce PEON ATION 22529 sid a:<\ jam a aclepiarsce oeina= --nlec a ans - even se voeeenty Oe 
aie IN AME OREM SGOU Ds 2 0 <tc ae + pclae ead elaiacaaaeno neu cancers onee/--50 vsseins 54 
Pec iota Mem etiReee ns soak cnt e nine daciseel sacs etincs scaccccess soeatecsse cece smn 9F 
