40 DEEr-SEA FISHES OF THE ATLANTIC BASIN. 



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

 three-elevenths ofthe length of the head ; interorbital 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 iuteroperculuni and subopereuluni 

 not prominent, and apparently replaced in part by the brauchiostegals. 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 ofthe branchial opening to the middle line of the body. Scales remarkably 

 small; those of lateral line very simple and more than a hundred in number. 



Dorsal with 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 tin- dorsal. Its height nearly the same as that of the dorsal. Caudal 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; fius sepia; iris black; pupil azure-blue. 



Scales very simple in form; those of tin- body arc rounded in outline and measure from 

 1.5 to 1.(1 mm., in diameter. Five pyloric cceca, moderately elongated. No trace of a swim 

 bladder. 



Radial formula: B. G; D. 21: A. 40; V. S; V. 5. 



Sixteen specimens of this species wen- obtained by the French expedition from the 

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

 varying from 865 to 2,115 meters. A specimen 8 inches in length was obtained by the Alba- 

 tross at station 2751, lat. 10° 57' N., Ion. 63° 12' W., in 68 fathoms. 



BATHYTROCTES, Gunther. 



Bathytroctes, GONTHER, Ann. and Mag. Nat. Hist., n, 187S, 249; Challenger 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 middle of the eye. Botli in- 

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

 palatine 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 

 fins moderately long, the former behind the ventrals. Adipose flu none. Caudal forked. 

 Gills very narrow; pseudobranchiae present: gill rakers long, lanceolate. Pyloric append- 

 ages in moderate number. Ova rather small. 



Bathytroctes is closely allied to Alepocephalus, 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 admission of its describer, quite as likely to 

 belong to some other genus — perhaps Alepocephalus. 



The type of this genus is Bathytroctes macrolepis, Gunther, from a depth of 2,150 fath- 

 oms, north of Celebes [Challenger station xcvm). — 1'>. squamosus, Alcock is from 740 fathoms 

 in the Arabian Sea. B. stomias, Gilbert, is from 877 fathoms, off Oregon and Washington. 



KEY TO THE SPECIES OF BATHYTROCTES. 



I. Dorsal fin far in advance of the anal Bathythoi tes 



A. Anal inserted nearly below middle of dorsal. Maxillary reaching to below posterior third of orbit. 



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



[Bathytroctes macrolepis] 



2. Scales moderate (57 in lat. line) Vertical tins moderate. (D. 17; A. It). Mouth very large. 



[B. stomias] 



3. Scales small (1001 in lat. line). Vertical fins moderate (D. 20: A. 17.) B. rostratcs 



