FISHES OF THE GULF OF MAINE 149 



THE LANTERNFISHES. FAMILY MYCTOPHID^E 



The most diagnostic external characters of the lanternfishes are their large 

 eves (situated close to the tip of the blunt snout), wide mouths gaping back beyond 

 the eye, one soft-rayed dorsal fin, a deeply forked tail, and the presence of a series 

 of phosphorescent organs as conspicuous pale spots along the sides. Some of them 

 have an adipose fin on the back behind the dorsal fin, but others lack this. When 

 present, this fin is so small and fragile that it is apt to be destroyed by the rough 

 treatment the fish receive in the tow net, in which they are usually taken. Among 

 Gulf of Maine fishes they most nearly resemble the anchovy (p. 124), pearlsides 

 (p. 151), and cyclothone (p. 153) ; but they are readily distinguished from the first 

 of these by the presence of phosphorescent organs and by the fact that the snout 

 does not project beyond the mouth, from the second by their much wider mouths, 

 and from the third by their much larger eyes. 



They are among the commonest fishes on the high seas, where they live at a 

 considerable depth by day but often rise to the surface at night, and a number of 

 them (especially of the genus Myctophum) have been taken along the continental 

 slope abreast of the Gulf of Maine. Hence one species or another may be expected 

 to stray in over the banks if not into the inner parts of the Gulf. 



The number and arrangement of the phosphorescent organs offer the readiest 

 means of identification within the family, and should a lanternfish be taken to 

 which the following account does not apply, we refer its captor to Goode and Bean 

 (1896) and to Brauer 60 or, better, suggest that it be submitted to the United States 

 Bureau of Fisheries to be named. 



52. Lanternfish {Mihoprora effulgens Goode and Bean) 



Jordan and Evermann, 1896-1900, p. 566. 



Description. — This curious little oceanic fish suggests the pearlsides (p. 151) in 

 the presence of an adipose fin and of well-developed phosphorescent organs, but its 

 mouth is much wider (it gapes back of the eye), its eye is even larger and situated 

 close to the end of the nose, and the dorsal profile of its head is very convex. There 

 is a very large and noticeable phosphorescent organ covering the entire tip of the 

 snout, including the margin of the orbit, and extending down over the edge of the 

 upper jaw, to which there is no parallel in the pearlsides or in any fish regularly 

 inhabiting the Gulf of Maine. There are also a number of small phosphorescent 

 spots arranged along the lower sides and on the lower surface as shown in the illustra- 

 tion. 67 



The arrangement of the fins (all of which are soft) is essentially the same as in 

 the pearlsides except that the dorsal (about 15 rays) and anal (about 16 rays) stand 

 relatively farther forward while the pectoral and adipose fins are proportionately 

 smaller and the caudal fin is more deeply forked. 



Color. — The color has not been described. Probably it is black or at least of 

 some dark shade, with the phosphorescent organs pale blue or green. 



« Die Tiefsee-Fische. Wissenschaftliche Ergebnisse der Deutschen Tiefsee-Expedition, 1898-99 (1906), Band XV, Teil I. 

 67 The structures along the lateral line shown in the illustration are large scales, not phosphorescent organs. 



