528 Bulletin 47 ', United States National Museum. 



245. NANSENIA, Jordan & Evermann. 



Namenia, JORDAN & EVERMANN, new genus, (groenlandica). 



Body elongate, cylindrical, covered with large, thin, silvery scales. 

 Head short. Mouth very small, terminal; premaxillaries very small; 

 maxillaries very short and broad, not extending to the front of the very 

 large eye, which forms more than half the depth of the side of the head. 

 Lower jaw and vomer with a narrow series of fine teeth ; no other teeth. 

 Dorsal fin short, inserted mostly before the ventrals, which are behind 

 the middle of the body ; anal fin small ; caudal small, forked, its central 

 part scaly ; pectoral rather narrow ; adipose fin well developed in the 

 young, but usually disappearing with age. Branchiostegals 3 or 4. 

 Pseudobranchise well developed. Air bladder large, silvery. No pyloric 

 cceca ; mucous membrane of stomach papillose. Arctic Ocean ; in deep 

 waters. An imperfectly known genus, apparently distinguished from 

 Microstoma, Cuvier, by the more anterior position of the dorsal, which is 

 behind the ventrals in Microstoma, and apparently by the stouter body 

 and the better development of the adipose fin. Most of the other char- 

 acters above mentioned are drawn from Microstoma and have not been 



verified in Nansenia. (Named for our friend, Fridtjof Nansen (1861 ), 



author of a study of the development of Myxine, and since noted as an 

 intrepid arctic explorer.) 



801. NANSENIA GRCENLANDICA (Reinhardt). 



B. 3; D. 11; A. 10; V. 10. " This fish appears to be intermediate 

 between Argentina and Microstoma, having the dorsal fin inserted for the 

 greater part in advance of the ventrals, and a series of fine teeth in the 

 lower jaw. Teeth on the vomer, none on the tongue. Adipose fin con- 

 spicuous. The height of the body is i the length of the head and n, of 

 the total." (Giinther, after Reinhardt.) Greenland. 



Microstomus grfJnlandicus, REINHARDT, Yidensk. Selsk. Naturv. Mathem. Afhandl., vm, 1841, 

 LXXIV, Greenland ; GUNTHEH, Cat., vi, 205, 1866 ; JORDAN & GILBERT, Synopsis, 290, 1883. 



246. BATHYLAGUS, Giinther. 



Bathylagus, GUNTHER, Ann. Mag. Nat. Hist., 1878, n, 248, (atlanticus). 



Body oblong, compressed, covered with thin, deciduous scales of mod- 

 erate size. Head short, compressed, the bones thin and membranaceous. 

 Mouth very narrow, transverse, anterior. Maxillary very short, dilated, 

 forming part of border of mouth. No luminous spots. Teeth in upper 

 jaw rudimentary, those in lower jaw very small, on edge of bone form- 

 ing a fine serrature ; a series of minute teeth across vomer and along 

 palatine. Eye very large. Pectorals and ventrals well developed, the 

 ventrals with light rays, opposite dorsal, which is in middle of length 

 of body ; adipose fin small, near caudal; anal moderate or long. Gill 

 opening narrowed, beginning opposite root of pectoral and extending 

 across isthmus, the gill membranes united, free from isthmus. Gill 

 rakers lanceolate, rather long ; gills small. Pseudobranchise well devel- 

 oped. Deep seas, 5 species known. 



