no. 2075. FISHES FROM SOUTHERN CALIFORNIA— GILBERT. 311 



XENOGNATHUS, new genus (Alepocephalidae). 



Closely related to Alepocephalus, differing principally in the struc- 

 ture of the mouth, the premaxillary greatly expanded, forming a 

 plate extending nearly horizontally backward, within which the 

 deep mandible is completely received. The anal fin is much longer 

 than the dorsal. The body is compressed, elongate, covered with 

 cycloid scales, and with well-developed lateral line. Teeth are 

 present in the premaxillaries, the mandible, and the front of the 

 palatines. Opercular flap voluminous; branchiostigals 6; gill mem- 

 branes separate. 



Type of the genus. — Xenognathus prqfundorum, new species. 



XENOGNATHUS PROFUNDORUM, new species. 



Plate 14, fig. 2. 



Type-specimen. — Cat. No. 75826, U.S.N.M., 525 mm. long, from 

 station 4390, off Catalina Island, lat. 33° 02' 15" N.; long. 120° 42' 

 W.; depth 1,350 to 2,182 fathoms. 



Dorsal, 19; anal, 28; pectoral, 12; ventrals, 6. Pores in lateral 

 line, 62 ; scales in an oblique line upwards and backwards from lateral 

 line to middle of back, 15. 



Head deeper than wide, its length one-third the total length with- 

 out caudal; greatest width of head 0.43 of its length; depth at occiput 

 0.54; depth opposite end of opercular flap 0.61 ; snout depressed at tip, 

 bounded anteriorly by a strong sharp osseous crest on the basal por- 

 tion of the premaxillaries; length of snout from eye, 0.29 of head; 

 width of snout opposite the outer ends of the terminal crest, 0.26; 

 frontal width opposite middle of eye, 0.27; longitudinal diameter of 

 eye, 0.22; maxillary reaching vertical from middle of eye, its length 

 measured from tip of snout, 0.45; length of premaxillary band of 

 teeth, 0.27, the bone extending but little beyond the last teeth; ver- 

 tical depth of mandible at symphysis, 0.6, the mandible shutting 

 completely within the premaxillaries in closed mouth, the premaxil- 

 lary teeth directed horizontally inward across the inferior aspect of 

 the mandible. 



Premaxillary teeth slender, cardiform, anteriorly in a very narrow 

 band, laterally in a single series. Mandibular teeth similar, in a nar- 

 row band or irregular series anteriorly. A single series of teeth on 

 the front of the palatines, which overlap the vomer anteriorly, and 

 are separated by a short distance on the median line. Vomer and 

 maxillary toothless. Gill-rakers 3 + 13 on outer arch, without teeth, 

 the longest 0.055 length of head. 



Origin of anal midway between middle of caudal base and margin 

 of opercular flap; base of anal 0.66 length of head. Origin of dorsal 

 under sixth anal ray, its last ray under the fourth before the last of 



