REPORT ON THE DEEP-SEA FISHES. 175 



The dorsal fin commences at some distance behind the origin of the anal and is 

 higher than the body underneath. Form of the anal fin as in Gonostoma elongatum; 

 it terminates at some distance from the caudal, the caudal peduncle being long and 

 slender. Caudal fin forked. Pectoral very narrow, nearly one-half as long as the head. 

 Ventral fins likewise very narrow, they reach to the vent, and their distance from the 

 latter is only two-fifths of that from the root of the pectorals. 



This fish is evidently scaleless, and uniform deep black ; the fins transparent. 



The luminous organs are still less developed than in Gonostoma elongatum, but their 

 arrangement is essentially the same. Two rows run near to the lower edge of the 

 abdomen ; the lowermost series containing four very small ones in front of the pectoral, 

 five between the pectoral and ventral, three between the ventral and anal, and very 

 small ones, whose number cannot be made out, along the base of the anal fin. The upper 

 abdominal series is represented only by a single organ at about the middle of the trunk. 

 The majority of the organs on the trunk consist of two parts, namely, a larger, circular, 

 glandular disk and a superimposed small eye-like spot, with a black margin and white 

 pupd. An oblong glandular mass occupies the lower margin of the tail on each side of 

 the root of the rudimentary caudal rays, but is absent, or present in a rudimentary con- 

 dition only, on the corresponding part of the upper side of the tail. Another similar 

 mass is embedded behind the upper portion of the maxillary bone, and is likewise 

 accompanied by an eye-like spot above. A small organ occupies the middle of the hind 

 margin of the praeoperculum. The organs which occupy the roots of each of the 

 branchiostegals are small and eye-like, and similar minute structures are scattered 

 in an irregular fashion along the middle, and also on the sides, of the abdomen. 



Gonostoma microdon. 



Gonostoma microdon, Giinth., Ann. and Mag. Nat. Hist., 1878, voL ii. p. 188. 

 Gydothone lusca, Goode and Bean, Bull Mus. Comp. ZobL, vol. x., 1883, p. 221. 



D. 13. A. 18-21. P. 9. V. 7. L. lat. 26 (?). 



Check naked. Teeth in the upper jaw very fine and numerous, with some larger ones 

 placed at regidar intervals. Eye small. 



Habitat. — Atlantic and Pacific (500 to 2900 fathoms). 



North-east of Bermuda, Station 60 ; depth, 2575 fathoms. Eight specimens, 1 to 2^ 

 inches long. 



North-east of Bermuda, Station 61 ; depth, 2850 fathoms. Three specimens, 1^ inches 

 long. 



North-west of Bermuda, Station 40 ; depth, 2675 fathoms. Two specimens, 1^ inches 

 long. 



