158 BULLETIN OF THE 



BATHYGADUS Gthr. 



A genus of Macruridae 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 maxiUa. 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 pseudobranchiae. Gill-rakers numerdus, moderate, lanceolate, with mi- 

 nute denticulations along the inner edges. Branchiostegal membrane free from 

 the isthmus, deeply cleft; branchiostegals 7, very stijff. 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 Lxxxix., 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 5; 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 .=(trongly 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 J 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 covpp all parts of the 

 head except the jaws and chin. 



The length of the heaxi is contained 5 times in total. Interorbital area flat, 



