604 PKOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. [lf'85. 



The maxilla extends beyond the vertical through the posterior mar- 

 gin of orbit, its length equal to that of postorbital part of head. Man- 

 dible two-thirds as long as head and equal in length to height of bod^-. 

 Jaws, vomer, and palate with bands of villiform teeth ; the vomerine 

 band V-shaped. 



Brauchiostegals 8. Pseudobranchise absent. 



Gill-rakers long and numerous, the longest slightly exceeding in 

 length the diameter of eye; 15 developed below the angle of the first 

 arch, besides several rudiments. 



Nostrils in front of the middle of the eye, separated by a slight inter- 

 space, the anterior nearer to its mate than to the tip of the snout. 



The muciferous channel upon the infraorbital ring shows in its course 

 several wide subcircular sinuses, closely approximated ; a similar row 

 upon the posterior edge of the preoperculum and continued forward 

 upon the under surface of the mandible ; the vertex also has a semi- 

 circle of similar sinuses. To the chain-like appearance of these rows 

 of ducts the s[)ecitic name has reference. 



The dorsal origin is slightly behind that of the pectoral, its distance 

 from the tip of the snout (32™™) about 7^ in total ; rays well developed; 

 in the anterior third of the fin, in a space equal to the length of the head, 

 were counted 20 rays, the longest of which is two-fifths as long as the 

 head. 



The anal origin is under the twenty-first dorsal ray ; its rays are shorter 

 than those of the dorsal. The pectoral extends to the vertical from the 

 eighteentli ray of the dorsal. It is four-fifths as long as the head. 



The ventral is composed of a simple filament, its origin slightly in 

 advance of the vertical through the pectoral origin, its length two-thirds 

 that of the head. It does not reach near to the vent, the distance of 

 which from the origin of the ventrals (30™™) is slightly greater than the 

 length of the head. 



Color, brownish yellow. Head and abdomen blackish. 



Bathyonus laticeps (Gthr.), from 2,500 fathoms in the mid- Atlantic, has 

 smaller eyes, broader head (if the measurements of the interorbital 

 space as given by Giinther afford a correct criterion), and a more fila- 

 mentous caudal prolongation. 



B. compressiis (Gthr.), from mid-Atlantic, 1,075-2,500 fathoms, and 

 from stations southeast of New Guinea, is, as its name indicates, much 

 more compressed, with swollen snout, and has the arms of the vomerine 

 V curved. 



B. gracilis (Gthr.), to which B. catena is probably most closely allied, 

 is from south of New Guinea, 1,400 fathoms, and, from the description, 

 would appear to be a long-bodied form. 



Bathyonus pectoralis, n. s. 



The type (37342, IT. S. N. M.) was taken at Albatross station 2380, 

 north latitude 28° 02' 30", west longitude 87° 43' 45", 1,430 fathoms. It 



