163 



Mouth large, moderately oblique ; the jaws perfectly equal in repose ; the 

 maxilla nearly reaches the preopercular angle and is dilated at its hinder end ; 

 no vomerine teeth. Opercles large ; the operculum produced into a membranous 

 spur behind ; the vertical border of the preoperculum very oblique. 



Scales extremely deciduous, smooth, cycloid, their average diameter one- 

 twelfth of an inch. 



The dorsal fin begins nearer to the tip of the snout than to the base of the 

 caudal, but behind the bases of the ventrals, which are much advanced, its last 

 ray falls in the vertical through the first or second anal ray ; adipose dorsal 

 entire. Pectorals long, extending beyond the tip of the ventral to the first or 

 second anal ray. 



The luminous organs are arranged on each side as follows : — A series ex- 

 tending close to the mid-ventral line from the isthmus to the base of the caudal, 

 and numbering four to base of ventral, three more to origin of anal, ten or 

 eleven more to hinder end of anal, and one more at base of caudal ; above this series 

 are the following, rather more scattered — one at the angle of the preoperculum, 

 two along the ramus of the mandible, two along the edge of the gill-opening, 

 one on the base of the pectoral, two on the base of the ventral, three in a 

 straight line along the middle of the flank, two above the anal, and one at the 

 base of the caudal. No luminous organ on the back of the tail. 

 Nine pyloric ca?ca. An air-badder. 



Colours in the fresh state : — Uniform silvery, with thickly scattered black 

 specks ; opercles and iris burnished silver. 



Length of mature females from not quite two inches to a little over two 



inches. 



Bay of Bengal, 98 to 102 fathoms; Andaman Sea, 370 to 419 fathoms. 



132. Scopelus pyrsobolus, Alcock. 



Scopelus pyrsobolus, Alcock, Ann. Mag. Nat. Hist. Sept. 1890, p. 21S, pi. VIII. fig. 3; Illustrations of thb 

 Zoology of the Investigator, Fishes, pl. XXX. fig. 3. 



D. 12. A. 13. P. 12. V. 8. 



Length of the head (not including a membranous prolongation of the sub- 

 operculum) about a third, greatest body-height about a fourth of the total length 

 without the caudal. Snout about a quarter as long as eye. Eyes large, round, 

 strongly convergent, bulging beyond the dorsal profile ; their diameter is a third 

 of the length of the head proper, and more than the mean width of the inter- 

 orbital space. Mouth wide, oblique ; the maxillary, which does not quite reach the 

 preopercular angle, is slightly dilated behind. Jaws equal in front. Villiform 

 teeth developed on the vomer. Opercles large, extremely thin, the vertical 

 border of the preoperculum oblique. 



