78 DEEP-SEA FISUES OF THE ATLANTIC BASIN. 



BENTHOSEMA ARCTICUM, (Lutken), Goooe and Bean. 



ScoiieluB ariiciia, LDtken, Spolia Atlantica, ii, 1892, 249, Fig. 6. 



A species apparently more closely related to B. MiiUeri than to any other form, bnt 

 having no posterolateral photophore and no break in the scries of superauals, the number 

 of which is fifteen or sixteen. It has two mediolaterals in subhorizontal line, continuous 

 with the two anterolaterals. It is a much shorter-bodied form than J>. {ilncialis, and has a 

 niucii sliortor and higher tirst (hirsal. Liitken's figure shows only one opercular photophore, 

 instead of two, which are customary. Kadial formula: 13. 9; A. 17; P. 14; V. 8. 



Liitken's types were four specimens obtained from Greenland and one from Davis's 

 Strait. Two of them have a large supracaudal luminous plate, and three others small 

 infracaudal luminous plates. 



BENTHOSEMA COLLETTI, (Lutken), Gooue and Bean. 



Scopehts Colleiti, L'jttken, Spolia Atlantica, ii, 1892, 249, Fig. 7. 



A species having the photojihores arranged somewhat as in B. arcticnm, but vrith the 

 two mediolaterals in a sub vertical line continuous with the last of the ventral photophores, 

 instead of approximately with the anterolaterals. There is no posterolateral photophore. 

 The superanals are in a continuous row, 10-17 in number. Head somewhat blunt; pectoral 

 short, as in JS. arcticnm, reaching about to the vertical from the origin of the first dorsal. 



Kadial formula: D.lo; A. 21; L, lat. 38. 



This species is described fi'om a single specimen in the Museum at Christiania, obtained 

 from the Pacific, GUO miles west of Cape Horn. 



LAMPANYCTUS, Bonaparte. 



LampnnijctuB, BoNAPATtTE, Faim. Ital., fasc. xxvil.— Gunther, Cat. Fish. Brit. Mus., v, 414 (as subgenr.s). 



Myctophid fislies, with long head, conical snout, limb of preoperculum obliciue; dorsal 

 about e(iual to or shorter than anal, and not overlapping. Lateral line not much enlarged. 

 Scales cycloid, smooth. No orbital spines. Scales smooth, those in the lateral line scarcely 

 larger than the others. Maxillary scarcely dilated behind. Precaudal photophores 1 or 2+1. 



KEY TO THE SPECIES OF LAMPANYCTUS. 



I. Pectorals long; precaudals in two groups (2+1, 3+1, or 2+2), the, last on or near end of lateral line. 



A. Mediolaterals 2; posterolaterals 2, nearly under soft dorsal. 



1. D. 12-13 ; A. 14-15 ; L. lat. 38-9 ; superanals 6-8+8-12 i,. crocodilus. 



2. D. 13; A. 15; L. lat. 32-3; superanals 7+6 l. alatus. 



B. Mediolaterals 3 ; posterolaterals 2, in advance of soft dorsal ; precaudals 3+1. 



1. D. 12-13; A. 14-13; L. lat. 36; superanals 5+5. 



a. Anterolaterals 2 ; pectoral extending beyond mediolaterals and to middle of anal 



L. GUNTHERI. 



2. D. 12-13; A. 13; L. lat. (?); superanals 7+5. 



a. Anterolaterals none ; pectoral not reaching mediolaterals or origin of anal L. waemingii. 



II. I'ectorals long; precaudals 4, iu continuous, nearly horizontal, row, not approaching end of lateral line. 

 A. Mediolaterals 2; posterolaterals 2, nearly under soft dorsal. 



1. D. 12; A. 16; L. lat. 38; superauals 7+8. 



a. Anterolaterals 3, horizontal, nearly in line with lowest raediolateral L. gemmifer. 



III. Pectorals short; j)recaudals 4, in low, nearly horizontal line, not approaching end of lateral line. 

 A. Mediolaterals 3. 



1. Posterolaterals 2, in advance of soft dorsal. 



a. D. 14 ; A. 12 ; L. lat. 35 ; superanals 4-5+5-6 l. ge.mellabii. 



b. D. 12-13; A. 19; L. lat. 33; superanals 6+5 L. c<eruleus. 



2. Posterolateral 1, placed under soft dorsal. 



a. D. 13- A. 12-13; L. lat. 36: superauals 5-7+5 l. lacerta. 



