gilbert: the lantern-fishes of japan 83 



Dorsal rays 12; anal rays 17; pectoral rays 11 or 12; ventral rays 8. Scales 

 of lateral line 34. 



Snout short, not bluntly rounded; mouth very oblique, the maxillary 

 broadened posteriorly, extending well behind eye and nearly to the preopercular 

 margin, which is not oblique. Eye large, more than one-third the length of 

 the head. Opercle posteriorly extended, wholly covering the upper and lower 

 pectoral photophores, notched opposite the pectoral base. Pectoral fin long, 

 extending beyond the origin of the anal. Anal much longer than the dorsal, 

 its origin under the middle of the dorsal base, its last ray under the adipose 

 fin. Ventrals reaching the anus. Scales all fallen, the scars indicating that 

 those along the lateral line were not at all enlarged. 



Photophores. — A minute pre-orbital, on the dorsal side of the nostril. A well- 

 developed subocular spot, not present in any other species of this genus, on 

 cheek below the hinder part of the eye, near the maxillary border. Lower 

 pre-opercular spot very smaU, opposite the expanded end of the maxiUary, the 

 upper large, placed entirely below the level of the eye, differing in this respect 

 strikingly from its position in M. pterotum. Suprapectoral vertically above the 

 lower infrapectoral and the second thoracic, situated obliquely above and 

 anterior to the pectoral base, slightly nearer to the pectoral than the lateral 

 fine. Lower infrapectoral anterior to the upper and but little below it. Tho- 

 racics 5, the anterior two interspaces wider than the posterior two; the first 

 pair nearest the median line, the fifth pair more widely separated, at base of 

 outer ventral rays. Supraventral vertically over the fifth thoracic, or even 

 slightly anterior to this line, its distance from lateral line about one-fourth its 

 distance from base of ventrals. Ventrals four, the second elevated, vertically 

 above the first, on a level with the second infrapectoral; the other three con- 

 tiguous to the midventral fine, the space between the first and third longer 

 than that between third and fourth. Supra-anals 3, sharply angulated, the 

 third on the lateral line, vertically above the first antero-anal, the second half- 

 way between lateral line and base of first anal ray, the third horizontally in 

 front of the second, very slightly above a line joining the second with the 

 elevated ventral. In the distribution of the photophores, this species agrees 

 with M. fibulatum, having the second ventral and the first two supra-anals in 

 line, the supraventral far above them. In M. pterotum, the first two supra-anals 

 and the supraventral are in line. Antero-anals 6, equidistant from the base of 

 fin. Posterolateral single, on the lateral line, vertically above the second or 

 third anal ray before the last. Postero-anals 5, the first above the base of the 



