DISCUSSION OF SPECIES AND THEIR DISTRIBUTION. 47 



small, with minute teeth on intermaxillary and anterior portion of mandible. Maxillary 

 short, broad, very thin, reaching slightly beyond the vertical from the anterior margin of 

 the orbit. Eye moderate, not entering into the upper profile; its diameter greater than the 

 width of the interorbital space, and two-ninths the length of the head. Snout shorter than 

 the diameter of the orbit. Vent midway between the root of the caudal and the pectoral. 

 Dorsal and anal similar in form and equal in extent, the anal beginning slightly behind the 

 vent, and the dorsal immediately above it. The bases of the posterior rays of the two fins 

 opposite. The ultimate rays of these tins are the longest, the length of the rays gradually 

 increasing from beginning to end. Caudal peduncle nearly twice as long as its own height. 

 Caudal deeply forked, with filamentous lobes, preceded above and below by numerous rudi- 

 mentary lays. Pectoral placed low, narrow, pointed : its length three-fifths that of the head. 

 Ventrals narrow, reaching to vent; their length equal to half that of the head. 



Skin tough, leathery, finely wrinkled, studded with small raised nodules, which extend 

 upon the rays of all the fins except the caudal; much more numerous below than above the 

 lateral line, which is very conspicuous, broad, straight, originating close behind the eye and 

 extending along the middle of the body and tail to the base of the caudal rays. 



Radial formula: D. 33; A. 33; P. 6; V. 5. 



A single specimen, 8 inches in length, was taken by the Challenger at station ccxxxn, 

 south of Yeddo, Japan, at a depth of 3-15 fathoms. 



ALEPOSOMUS, Gill. 

 Aleposomus, Gn.i , American Naturalist, xvm, 1884, 433. 



Alepocephalids with body elongate, scaleless. The skin is thick, finely rugose, with a 

 considerable number of small nodules upon the belly, and sometimes also upon the sides 

 and the lower part of the head. Lateral line, wanting. Mouth moderate, with minute teel h 

 upon the mandible and premaxillary. Palatines, tongue, and pharyngeal bones probably 

 toothless. Dorsal and anal fins opposite, similar in form and equal in length. Caudal 

 probably forked. Vent behind the middle of the body. Gill openings wide. 



There are two species in this genus: A. Copei, Gill, with large oval orbit, large mouth, 

 high vertical tins, and with numerous nodules upon the sides, and A. socialis ( Vaillant), with 

 smaller eye, its outline projecting above the dorsal outline, smaller mouth, and nodules 

 apparently concentrated on the lower parts of the head and the anterior portion of the bell}'. 



ALEPOSOMUS COPEI, Gill. (Figure 51.) 

 Aleposomus Copei, Gill, American Naturalist, win, 1884, 433. 



Body compressed, its outlines sloping from head to middle of the caudal peduncle; 

 its height 5.J in its length. 



Length of the head 3% in length of body. Snout short, declivous, its length half the 

 horizontal diameter of the eye and about one-fifth that of head. Mandible scarcely extend- 

 ing beyond upper jaw. Maxillary extends to vertical from middle of orbit. Small teeth 

 upon mandible and premaxillary. Eye very large : its diameter half the length of the head ; 

 its upper outline does not project above the dorsal profile, as in .1. sodaUs. Gill opening 

 large. Skin thick, slimy, no lateral line distinguishable. No scales present, but numerous 

 tubercles upon the sides of the body. None arc perceptible on the head. Vent midway 

 between the origin of the ventral and the tip of the last dorsal ray. Dorsal origin equidis- 

 tant from the gill opening and the base of the middle caudal rays; highest in its middle 

 portion, rounding forward and behind. Anal inserted immediately under the dorsal; simi- 

 lar in shape and equal in extent. Caudal, though mutilated, was undoubtedly emarginate, 

 and probably forked. Accessory rays, characteristic not only of A leposomus but of Xenoder- 

 michthys, are not conspicuous. The pectoral is inserted very low down, close to the pos- 

 terior angle of the preopercular flap, and appears to have been feeble; its diameter not 



