132 
2. Sternoptyx Hermann. 
(HERMANN, Der Naturforscher, XVI. 1781, p. 8). 
Trunk much elevated and compressed, passing ventrally 
abruptly with a more or less right angle into the short and 
compressed tail; the angle being filled up by a transparent fold 
of the integument, resembling thin cartilage. A similar structure 
forms the ventral edge of the trunk. Cleft of mouth subvertical, 
its upper margin formed by the very short intermaxillaries and 
maxillaries. Lower jaw received in the upper, its posterior 
inferior angle has a short spine as also the angle of the prae- 
operculum and the symphysis of the humeral bones. At the 
symphysis of the pelvic bones two spines, one looking forward, 
the smaller backward. Behind the anus a bifid spine. Before 
the dorsal, the origin of which is situated behind the middle 
of the body, a translucent pear-shaped plate, which has its upper 
border dentated, strengthened along its hindmargin by a strong 
spine. Anal arising on the broad transparent integumentary 
fold between trunk and tail. The low adipose fin begins imme- 
diately behind dorsal and reaches nearly to the anterior rays 
of the caudal, which is broad and forked. Pectorals close to 
the ventral profile, surpassing the base of the ventrals. Ventrals 
small. Eye large, snout very short. Numerous small unequal 
teeth in the jaws. Palate edentulous. No scales. Luminous 
organs: one behind and one below the eye, one opercular, a 
group on branchiostegal membrane, a group on isthmus, a series 
along ventral edge, one series between ventrals and anal, above 
anal, behind anal and above pectorals. Gillopening very wide, 
gillmembranes attached to the isthmus. 4 gills. Pseudobranchiae 
present. Gillrakers moderate. 
I. Sternoptyx diaphana Herm. 
Sternoptyx diaphana Hermann, Der Naturforscher, XVI. 1781, p. 8. 
Sternoptyx diaphana Giinther, Challenger Report Deep-sea Fishes, 1887, p. 168. 
Sternoptyx diaphana Brauer, Deutsche Tiefsee-Exp. Tiefseefische, 1906, p. 115. 
Sternoptyx diaphana Zugmayer, Camp. Scient. Monaco, XXXV. IQII, p. 54. 
Sternoptyx diaphana Max Weber, Siboga-Exp. Fische, 1913, p. 22. 
B...§5. D. 9125 ,A4 135 —1As BE oe Se 
Height generally equal to distance between snout and base 
of tail but varying very much according to length. Length 
of head 2'/, to more than 3, generally more or less below 3. 
