DISCUSSION OF SPECIES AND THEIR DISTRIBUTION. 145 



HISTIOBRANCHUS, Gill. 



Eittiobranchus, Gill, Proc. U. S. Nat. Mus., 1883; vi, 255, 1890, xiii, 161. — Jordan and Davis, loc. cit., 672. 



Synapliobrancliids with origin of dorsal almost as far forward as the base of the pec- 

 toral and far in advance of the anal. Vent nearly in the middle of the length of the body. 

 Vomerine teeth in two patches, that in front being the larger. (Gill.) 



HISTIOBRANCHUS INFERNALIS, Gill. (Figure 165.) 



Histiobranchus infernalia. Gill, loc. cit. 



Syiiaphobranchiis iufernalis, Gt'NTilER, Challenger Report, xxii, 254. 



Body moderately elongated and comj)ressed; its height at the anus equals .56 of the 

 length and the greatest width above the stomach being less than two-thuxls of the 

 height. The head forms about one-ninth of the total length, and its width is a little less 

 than one-half its length; the snout is moderate, the length being less than the greatest 

 width of the head. The eye is also moderate, its diameter being much less than one-half 

 the length of the snout. 



The upper jaw is nearly one-tenth of the total length and the lowei' jaw a little more. 



The dorsal commences not far behind the vertical from the root of the pectoral, while 

 the anal arises little nearer the snout than the end of the tail; both are moderately devel- 

 oped. 



The pectorals are considerably shorter than the snout. 



The color in life is said to be an almost uniform dark jjlumbeous, but in alcohol the 

 trunk is dark yellowish brown, becoming almost black on the abdominal region and around 

 the pectoral as well as on the intermandibular integuments and around the pectoi'als, while 

 the dorsal and anal are whitish except towards the posterior fourth of the length, where 

 they are very dark or blackish. 



A specimen, No. 33279, was taken by the Albatross at station 2037, hit. 38° 30' 30" N., 

 Ion. 69° 08' 25", W., in 1,731 fathoms. 



Another species of the same genus, characterized mainly by stouter body and lower 

 vertical fins, is HisUohranclins hathybius, Giinther {Synapkobranchus bathybius, Giinther, 

 Ann. and Mag. Nat. Hist, xx, 1877, 415, Challenger Report, xxii, 251, pi. LXii, fig. B), a 

 stouter, chunkier form, with shorter snout and tail, and smaller fins, obtained in the 

 Pacific and Indian oceans, at depths from 1,375 to 2,050 fathoms. 



Family MUR^ENESOCID^^. 



Con gri formes Mnranesoces, Bleeker, Atl. lehtli. lud. neerl., i, 1864, 19. 

 Muriniesocina, GtiNTHER, Cat. Fish. Brit. Mus., viil, 1870, 20. 

 Murwnesochiw, .Jordan .and Gilbert, Bull, xvi, U. S. Nat. Mus., 1882, 387. 



Mtmruesocidw Cope, Proc. Am. Ass. Adv. Sci., 1871 (1872), 334.— Gill, Arr. Fam. Fish. 1870, 20; Proc. U. S. 

 Nat. JIns., 1890, 321.— Jordan and Davis, Rep. U. S. F. C, 1888 (1891), 643. 



Anguilloid apodals, with thick skeleton, thin scaleless skin, and tail surrounded by 

 vertical fins; pectoral well developed ; jaws of moderate length; vomer well armed; pos- 

 terior nostril not lateral; tongue narrow, its margins adnate; gill openings rather wide. 

 "Branchiostegal membrane connecting the opposite sides below, the epiiiharyngeals 

 reduced to one pair, and the uypoiiharyngcals linguiform and encroaching on the fourth 

 branchial arch." 



"The characters which apjiear to distinguish the Mnrcvne^oces best from the Anguillids 

 and Cougrids or Leptocephalids are the low position on the hj'omandibular of tlie condyle 

 for the operculum, the slender branchial arches and the development and position of the 

 hypopharyngeals and epipharyngeal s, the union of the opposite branchiostegals by the. 

 inferior branchiostegal membrane, and the want of freedom of the tongue. Whether the 

 other genera that have been closely associated with Murwnesox [Hoplimms, Oxyconger,Xeo- 

 conger, Xfttasfoma, and Saurenchelys) are related to the family can only be determined by an 

 19 08- No. 2 10 



