114 DEEP-SEA FISHES OF THE ATLANTIC BASIN. 



KEY TO THE SPECIES. 



A. Dorsal and anal moderate (D. 19 ; A. 20). Loral spot longer than eye Malacosteus NIGER 



B. Dorsal and anal short (D. 15; A. 15). Loral spot shorter than eye M. ciiokistodactylus 



MALACOSTEUS NIGER, Ayres. (Figure 138.) 



Malacosteus niger, Ay-res, Journ. Bost. Soc. Nat. Hist., 1849, 53. — Gunther, Cat. Fish. Brit. Mus., 1864, 

 v, 428. — Goode and Bean, Bull. Essex Institute, 1879. 



A Malacosteus with a somewhat slender body, its height about one-eight of its length, 

 without caudal; with large branchial opening, and with comparatively long dorsal and anal 

 tins, nearly opposite (the dorsal slightly in advance), falcate, strong. Luminous body almost 

 ereseentie, its length greater than diameter of eye. Fangs shorter than diameter of eye. 

 Ventrals shorter than base of dorsal. Black, with numerous light dots over entire body. 



Eadial formula: D. 19; A. 20 ('?); P. 3 ("?); V. 5. 



For a long time only a single specimen of this species was known, the type of Ayres's 

 description, 8i inches in length, which was picked up at sea in 40° N. lat., 50° W. Ion. 

 The BUike obtained a single specimen at Station cxlv, off Barbados, at a depth of 317 

 fathoms. The Albatross obtained several specimens: No. 35526, TJ. S. N. M., from station 

 2211, in 39° 35' N. lat., 71° 18' W. Ion., at a depth of 1,064 fathoms; No. 32169, U. S. N. M., 

 (No. 797, Gloucester donation); No. 39220, TJ. S. N. M., 6J inches in length, in 37° 46' 30" N. 

 lat., 73° 50' 30" W. Ion. ; a specimen from station 2,584, in 39° 05' 30" N. lat., 72^> 23' 20" \Y. 

 Ion., at a depth of 541 fathoms. 



Giinther has described a species very closely related under the name of Malacosti us 

 indicus (Challenger Report, xxn, 214, pi. irv, tig. B.), from near the Philippines, 500 fath- 

 oms, and in the Andaman Sea (Alcoch) 650 fathoms. 



MALACOSTEUS CHORISTODACTYLUS, Vaillant. (Figure 139.) 



Malacosteus choristodaclylus, Valllant, Exp. Sci. Travailkur et Talisman, xxu, 18ns, ids, pi. viii, fig. 4. 



A Malacosteus with a comparatively stout body, its height nearly one-fourth of its 

 length, its thickness six one-hundredths of same; with immense branchial opening by the 

 extent of which the length of the head is seemingly reduced to one-eighth of the length of 

 the body, and with comparatively short dorsal and anal fins inserted nearly opposite each 

 other, apparently rounded and not falcate; caudal fin very small; luminous body under eye 

 subquadrangular, its greatest length less than the diameter of the eye; ventrals longer 

 than base of anal, much longer than base of dorsal; the longest ray apparently equal to the 

 distance from insertion of anal to the end of middle caudal rays; length of strongest fangs 

 greater than diameter of eye. Black, apparently without small luminous dots upon the 

 body. 



Eadial formula: D. 19; A. 20; C. 12+; P. 5; B. 6. 



This species was described by Vaillant from three specimens, two from the coast of 

 Morocco in 1,400 to 1,635 meters and one from the Azores in 2,220 meters. The species is 

 very distinct from M. niger and easily recognized. 



PHOTOSTOMIAS, Collett. 

 rhotostomias, Collett, Bull. Society Zoologiquo de France, 1889, 291. 



A genus allied to Malacosteus, characterized by the absence of pectoral and adipose 

 dorsal fins, and the absence also of teeth upon the palatines. The body is compressed, skiu 

 naked; ventrals in advance of the middle of the body; vent behind the middle of the body; 

 opercula rudimentary. A series of long, crooked teeth in the intermaxillary; teeth upon 

 the lingual and pharyngeal bones, but absent upon the vomer. Two post-orbital photo- 

 phores. Two rows of photophores along the sides of the belly, and a great number of small 

 luminous points scattered over the entire surface of the body. Type, P. Guenii, Collett. 



