214 THE VOYAGE OF H.M.S. CHALLENGER. 



Malacosteus niger (PI. LIV. fig. C). 



Malacosteus niger, Ayres, Journ. Bost. Soc. Nat. HLst., 1849, p. 53, pi. v. 

 D. 19. A. 20. P. 5. V. 6. 



The specimen of which Dr. Ayres has given an excellent description and figure, 

 was 8^ inches long, and picked up at sea in the Atlantic in lat. 42' N., long. 50° W. 

 Its mandible is armed with a series of slender, more or less curved teeth unequal in 

 size ; the largest occupy the anterior half of the bone and are four in number, a few smaller 

 ones being placed between them in an irregular fashion; also the extremity of the 

 mandible is armed with a longer curved tooth, but shorter than the lateral large ones. 

 The caudal peduncle is very narrow behind, about two-thirds as long as the base of the 

 dorsal fin. Base of the ventral fin midway between the caudal and the posterior 

 luminous organ. 



These are the principal characters by which this fish seems to specifically difi"er from 

 its congener from the Indian Ocean. 



The figure of the dentition is copied from Dr. Ayres' original drawing. 



Malacosteus indicus (PI. LIV. fig. B). 



Malacosteus indicus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 181. 

 D. 18. A. 20. P. 2. V. 6. 



The fang on the extremity of the mandible is as strong as any of the lateral teeth, 

 more strongly bent, and directed forwards and outwards. Of the lateral mandibulary 

 teeth two exceed the others in length and strength ; the anterior is at no great distance 

 from the terminal fang, and the space between them is filled up by three or four smaller 

 teeth which decrease in size forwards. The posterior large fang is more remote from the 

 anterior and separated from it by smaller teeth varying in size. The caudal peduncle is 

 less narrow than in the Atlantic species, and its length less than one-half of the length 

 of the dorsal fin. Base of the ventral fin nearer to the caudal than to the posterior 

 suborbital luminous orgafa. Caudal fin emarginate. Deep black. 



One specimen, 4 J inches long, was obtained near the Philippine Islands (Station 214), 

 in 500 fathoms. It is extremely similar to Malacosteus niger, and a detailed description 

 is therefore rendered unnecessary by the excellent account which Ayres has given of that 

 species. 



Mr. Murray^ observes: — This fish "had between the maxilla and the eye on either 

 side two spots, the posterior one round and of a beautiful light yellowish-green colour, 

 the anterior one larger, club-shaped (the head of the club pointing back), and of a dull 

 1-ed colour. The specimen was .... entirely black, with minute dots over the surface. " 



» Narr. ChaU. E.xp., vol. i. p. CG9. 



