124 DEEP-SEA FISHES OF THE ATLANTIC BASIN. 



Pectorals well developed, close to tlio lower profile; veiitrals small; pelvic bone with 

 a bifid spine in front jjointing forwards. Tlie dorsal flu occupies the middle of the back and 

 consists of a triani;iilar bony lamella, very thin iu front, but strengthened along its hiud 

 margin, and followed by several rays. Adipose fin absent, or represented by a very low 

 membranous fringe of the dorsal margin of the tail. The anal fin is incompletely developed, 

 extending from tlie veut to the root of tlie caudal fin, its rays being rudimentary, widely 

 set, and scarcely free. Caudal fin broad and forlccd. Gill opening very wide, tlie gill mem- 

 brane being attaclied to tiie istiimus, A luminous organ occupies the inner side of the oper- 

 culum close to its end; another is placed at the anterior end of the ceratobyal, and, finally, 

 a very large glandular mass is lodged on the upper edge of the anterior end of the clavicle. 

 (]ills4; the brancliial arches are long, not angularly bent, the branchial slits being closed 

 by a membrane in their upper portion. Only a few of the gill rakers are prolonged, needle- 

 sliaped, and widely set, the others being quite rudimentary. Pseudobranchije present. 

 (GiiHther.) 



STERNOPTYX DIAPHANA, Lowe. (Figure 146.) 



Sternopiyx diaphana, Hermann, Naturforscher, 1781, xvi, 8, taf. 1. figs. 1 and 2 (bad), and xvii, 249 (cop. 

 by Wai.haum, Artedi, in, tab. 1, figs. 1 and 2. — Bloch, Syst. Ichth. ed. Schneider, 1801, 494, pi. 35).— 

 CuviEK, Regne Anim. 2nd edit., pi. 13, fig. 1. — Cuvier and Valenciennks, Hist. Nat. Poiss., xxii, 

 415.— Lowe, I'roc. Zodl. Soe. London, 1843, 85. — Gunther, Cat. Fish. Brit. Miis., v, 387; Cliallenger 

 Report, x.xil, 11)9-170, pi. XLV, figs. D, D'. — Vaillant, Exp. Sci., TiavaiUeur et Talisman, 102. 



Stemoptyx Hermanni, LacepiSde, Hist. Nat. Poiss. v, 613. 



Height of the body equals distance between extremity of the snout and commencement 

 of the tail. Tail very short. luterorbital space slightly concave. Posterior limb of preoper- 

 culum borders hind part of the orbit, and descends iu a very oblique line, terminating in 

 two points. Pectoral fin scarcely reaching to the ventrals, which are very small. (Giinthcr.) 



Radial formida: B. 5; D. 10-12; A. 12; P. 10; V 3. 



This grotesquely shaped and interesting fish was first discovered in the West Indies in 

 1774 by Herjnann. 



It was described by him in 1781 in the N'aiurforscher. It was nest observed iu the 

 mid- Atlantic in AugTist, 1842, when Lowe obtained a specimen taken between Madeira and 

 St. INIarys, the southernmost of the Azores, about 80 miles to the southeast of the latter 

 island, in a calm, smooth .sea. It was among the rarest of fishes until the tune of the Chal- 

 lenger, which upon its cruise around the world obtained quite a number of specimens in the 

 mid-Atlantic, the Australian seas, and in various places in the South Pacific, and about the 

 same time the vessels of the U. S. Fish Commission and Coast Survey began to obtain it iu 

 the western Atlantic. The manner of its occurrence has been very puzzling. Although 

 two or three siiecimeus were obtained at the suiface, they were usually caught up iu a 

 dredge or ti-awl from 500 to 2,500 fathoms, and the peculiarities of its distribution have 

 given rise to much s]tecnlation. A study of the list of specimens published in the Chal- 

 lenger Report would .seem to indicate that the fish inhabits all depths from the surface 

 downward. Dr. Giinthcr is unable to accept this as an indication of that state of affairs, 

 and is of the oiiinion that its frequent capture would seem to be only a proof of its abun- 

 dance in all tropi(-al .seas and of tlie slowness of its movements, which prevent it from going 

 out of the dredge or net. He believes that although it and Argi/mpelecus are pelagic fishes 

 wliich live in shoals, it is possible that they may descend to or beyond the hundred-fathom 

 line during the daytime. Wliy during the daytime only is hard to understand, and it 

 seems to us perhaps judicious to admit that we do not know the conditions of its distribu- 

 tion as regards depth, and to wait for further information before foiining any opinion. r>r, 

 Giinthcr has studied all of the Challengers specimens carefully and has arranged them in 

 groups with reference to the form of the body. 



The numerous specimens collected by the Challenger diff"er not inconsiderably in the 

 shape of the body, which, in some specimens, is much more oblique than iu others; in the 

 width of the ui)per surface of the head and neck, and, finally, in the size of the eye, which in a 

 specimen 50 millimeters long is 8 millimeters wide, and in another specimen of the same 



