158 BULLETIN OF THE 
BATHYGADUS Gthr. 
A genus of Macruride with large terminal mouth, prominent nape, no teeth, 
lanceolate gill-rakers, free notched branchiostegal membrane, high vertical fins, 
first dorsal composed largely of branched rays, anal fin set far back. Head 
large, fleshy, without prominent ridges, spiny armatures, or external depres- 
sions. Nape elevated, hump-like. 
Snout broad, obtuse, not produced. Mouth terminal, very large. Suborbital 
ridge very low, not joined to the angle of the preoperculum. The maxillary 
may be received entirely within a groove under the prefrontal and suborbital 
bones, its tip narrowed and blade-like. Intermaxillaries protractile downwards, 
separated anteriorly, rib-shaped, compressed vertically, very broad and without 
true teeth, and provided posteriorly with a short flange which is received under- 
neath the maxilla. Mandible received within the intermaxillary bones, without 
true teeth, but with minute asperities, similar to those in the intermaxillaries. 
A barbel. Vomer and palatines toothless. 
No pseudobranchie. Gill-rakers numerous, moderate, lanceolate, with mi- 
nute denticulations along the inner edges. Branchiostegal membrane free from 
the isthmus, deeply cleft; branchiostegals 7, very stiff. Gill-opening very wide. 
Operculum with a blunt spine-like prominence at its angle. Ventrals below 
the pectorals, many rayed, the anterior rays produced. 
Dorsal consisting for the most part of branched rays. 
Scales cycloid, plain : lateral line strongly arched over the pectoral. 
Bathygadus arcuatus, n. sp. 
The type is a specimen, 325 mm., obtained by the steamer “ Blake ” at Sta- 
tion LXXXxIXx., off Martinique, at a depth of 334 fathoms. A much larger 
specimen, 580 mm., was taken by the Fish Commission at Station 2394. This 
specimen is referred to as a collateral type. 
The body is shaped much as in Chalinura simula, but the nape is still more 
convex. Its greatest height (57 mm.) is 53 in its total length. The back is 
gibbous, the dorsal outline rising rapidly from the interorbital region to the 
origin of the first dorsal, whence it descends gradually to the end of the tail. 
The scales are moderate, cycloid, subovate, without armature ; those of the 
abdominal region and those above the pectorals the largest. The lateral line 
is strongly arched over the pectorals, the length of the arched portion con- 
tained about 3} times in the straight portion ; the greatest height of the arch 
is about ¢ of the length of its chord. 'The number of scales in the lateral line 
is about 140, eight rows of scales between the origin of the dorsal and the arch 
of the lateral line, 13 or 14 rows of scales between the vent and the lateral 
line counting backwards, 22 counting forwards. Scales cover all parts of the 
head except the jaws and chin. 
The length of the head is contained 5 times in total. Interorbital area flat, 
