40 DEEP-SEA FISHES OF THE ATLANTIC BASIN. 



together, the anterior near the middle of the length of the snout. Eye large; its diameter 

 three-elevenths of the length of the head ; iiiterorbital space two-elevenths. Gill opening wide ; 

 operculum for the most part membranaceous, its elements being very imperfectly ossified; 

 preoperculum curved, thickened on its anterior edge; the interoperculum and subopercnlum 

 not prominent, and apparently rejilaced in part by the branchiostegals. Gill rakers, about 

 15 below angle. 



The vent is a little behind the middle of the total length. Lateral line extending from 

 the upper part of the branchial opening to the middle line of the body. Scales remarkably 

 small; those of lateral line very simple and more than a hundred in nund>er. 



Dorsal witli its outline a little convex, lower behind and ending at a distance from the 

 caudal equal to the length of its own base, which is equal to about one-eighth of the length of 

 the body; anal more than twice as long, beginning near the vent and terminating a little 

 behind the dorsal. Its height nearly the same as that of the dorsal. Gaudal moderately long ; 

 its length equal to one-seventh of the length of the body, slightly emarginate; pectoral small ; 

 ventrals very short. 



Color reddish brown; head a beautiful azure-blue; fins sepia; iris black; pupil azure-blue. 



Scales very simple in form; those of the body are rounded in outline and measure from 

 l.n to l.(i mm., in diameter. Five pyloric ccpca, moderately elongated. No trace of a swim 

 bladder. 



Itadial formula: B. 6; D. 21; A. 40; P. 8; V. 5. 



Sixteen specimens of this species were obtained by the French expedition from the 

 coast of Morocco to Soudan, from the Banc d'Arguin, and from the Canaries, at deiiths 

 varying from 8G5 to 2,115 meters. A specimen 8 inches in length was obtained by the Alba- 

 tross at station 2751, lat. 10"= 57' N., Ion. G.'P 12' \V., in (J8 fathoms. 



BATHYTROCTES, Gunther. 



Bathytroctes, Gunther, Ann. ami Mag. Nat. Hist., ii, 1878, 241); Clialloiiger Report, xxii, 225; Study of 

 Fishes, 664. 



Body rather elongate, compressed, covered with scales of moderate size. Cleft of the 

 mouth rather wide, the maxillary extending to below the nuddle of the eye. Both in- 

 termaxillary and maxillary armed with a series of minute teeth, as is also the mandible; 

 l)alatiue bones with similar teeth; those on the latter often weak and deciduous. Vomer- 

 ine teeth present or absent. No teeth on the tongue. Eye very large. Dorsal and anal 

 tins moderately long, the former behind the ventrals. Adipose fin none. Caudal forked. 

 Gills very narrow; pscudobranchia' present; gill rakers long, lanceolate. Pyloric ai)pend- 

 ages in moderate number. Ova rather small. 



Batht/frocfrs is closely allied to Alcjwrephnlus, from which it differs chiefly in the pres- 

 ence of teeth on the maxillary. Ten species have been described, seven of which are from the 

 Atlantic. One of these, B. attritus, is, by the admissi(m of its describer, quite as likely to 

 belong to some other genus — i)erhaps Alcpoccphah(s. 



The tyi>e of this genus is Bathytroctes macrolcpis, Giinther, from a depth of 2,150 fath- 

 oms, north of Celebes {Challouier station xcviii). — B. siinnmosus, Alcock is from 740 fathoms 

 in the Arabian Sea. B. stovtias, Gilbert, is ti'om 877 fathoms, off Oregon and Washington. 



KEY TO THE SPECIES OF BATHYTROCTES. 



I. Dorsal fiu far in ailvance of the anal BATiivxiiocTES 



A. Anal inserted nearly below middle of dorsal. Maxillary reatliiuj; to ImIow jiosti^rior third of orliit. 



1. Scales large (42 in lat. line). Vertical fins short. (D. 15; A. 11.) 



[Batiiytuoctes macuolepis] 



2. Scales moderate (57 in lat. line) Vertical fins moderate. (1). 17; A. 14). Mouth very large. 



[B. .STOMIAS] 



3. Scales sm.iU (100 f in hit. line). Vertical tins moderate. (D. 20: A. 17.) B. uosTitATUS 



