DISCUSSION OP SPECIES AND THEIR DISTRIBUTION. 123 



Gunther described this geuus :iiid species from a specimen ^ inches long, obtained 

 south of the Philippine Islands, at Challcnucr Station ccxiv, at a depth of .500 fathoms. He 

 had previously obtained, in 18G8, the specimen collected by Lowe at Magdaleua. The 

 Albatross obtained a single specimen from station 2392, in 28° 47' 30" N. lat., 87° 27' W. 

 Ion., at a depth of 724 fathoms. 



The capacity of this form for swallowing fishes greater in size than itself appears to be 

 as great as that of Chiasmodus, as may be understood from an inspection of figure c' in 

 Giinther. 



Family STERNOPTYCHID^^. 



Sternojiti/chido!, Gunther, Cat. Fish. Brit. Mus., v, 1864, 384, (part group Sternoptychina). — Gill, Arr. Fami- 

 lies Fishes, 1872, 15 (FamUy No. 153, name only) ; Proo. U. S. N. M., vii, 1884^ 350 — Joudan and 

 Gilbert, BuU. xvi, U. S. Nat. Mus., 283.— Jordan, Cat. Fish. N. Am., 46. 



Malacopterygians with compressed vcntradiform body, carinated contour, deeply and 

 obliquely cleft and subvertical mouths, whose upper margin is constituted by the supramax- 

 illaries as well as the intermaxillaries ; branchiostegal arch near and parallel with lower 

 jaw, scapular « itii an inferior projection, and with one or more of the neural spines abnor- 

 mally developed, and projecting above the back in advance of the dorsal fin. (Gill.) 



KEY TO THE GENERA AND SPECIES. 



I. Body naked. 



Abdominal outline nearly continuous in a sigmoid curve, a single producedspike-like neural spine in front 



of the dorsal tin, and about 5 branchiostegal rays Sternoptychina, Gill 



A. Teeth in the jaws iu several series ; dorsal flu with spinous dilatations Steknoptyx 



1. Height of body eifual to length, without caudal Sterxoptyx diaphana 



Abdominal outline abruptly contracted in advam-e of anal, several produced neural spines constituting 

 a uniform edge iu advance of dorsal, and about 9 branchiostegal rays Argyropelecin j;, Gill 



A. Teeth in the jaws iu a single series, minute Argyropelecus 



1. Tail spineless. 



a. Mandible with flat spine at its lower angle. 



i. Pectoral fin extending nearly to origin of .anal A. HEMIGYMN08 



ii. Pectoral extending to ventral A. Olfeksii 



b. Mandible without spine A. D'Urvillii 



2. Double row of spines along side of tail A. aculeati'S 



B. Teeth in jaws long and recurved Sternoptyciiides 



II. Body covered with large, thin, deciduous scales. Anterior spinous dilatation of dorsal fin lacking. 



Polyipnina 

 A. Lummous organs much developed Polyipnus 



STERNOPTYX, Herm.vnn. 



Sternoplijx, Hermann, Naturforscher, xvi, 1781-2. — Cuvier and Valenciennes, Hist. Nat. Poiss., xxii, 412. — 

 Gunther, Cat. Fish. Brit. Mus., v, 386; Challenger Report, xxii, 169, pi. xlv, figs. D, D'. 



Body much elevated and compressed, passing abruptly into a short and compressed 

 tail, the angle made by the hind margin of the trunk and the lower edge of the tail being 

 filled up by a broad fold of the integument, of peculiar transparent appearance, resembling 

 thin cartilage. This fold bears the anal fin and is supported by interha-mal rays. The 

 greater portion of the body is scaleless and covered with a silvery pigment. A series of 

 luminous spots runs along the lo(ver edge of the abdomen and is separated from that of the 

 other side by a cartilaginous fold occupjang the median line of the abdomen; another series 

 runs on each side of the isthmus; a row of thi-ee above and behind the root of the ventrals, 

 and another I'ow of three above the vent. The luminous organs on the lower part of tlie 

 tail consist anteriorly of a row of four, of wliicli the first is prolonged along the back as a 

 narrow band, terminating about the middle of the depth of the body in a globular black 

 spot with a white center; posteriorly in front of the caudal I'ays there is another row of four 

 small spots. 



