Adaptations of Fishes 61 
Entirely different are the photophores in the midshipman 
or singing-fish (Porichthys), a genus of toad-fishes or Batra- 
choidide. This species lives near the shore and the luminous 
spots are outgrowths from pores of the lateral line. 
In one of the anglers (Corynolophus reinhardtt) the complex 
bait is said to be luminous, and luminous areas are said to 
occur on the belly of a very small shark of the deep seas of 
° 
el a 
a6 
Fie, 46.—Htmopterus lucifer Jordan and Snyder. Misaki, Japan. 
Japan (Etmopterus lucifer). This phenomenon is now the sub- 
ject of study by one of the numerous pupils of Dr. Mitsukuri. 
The structures in Corynolophus are practically unknown. 
Photophores in Iniomous Fishes.—In the /niomz the luminous 
organs have been the subject of an elaborate paper by Dr. 
R. von Lendenfeld (Deep-sea Fishes of the Challenger. Ap- 
pendix B). These he divides into ocellar organs of regular 
form or luminous spots, and irregular glandular organs or 
luminous areas. The ocellar spots may be on the scales 
of the lateral line or on other definite areas. They may be 
raised above the surface or sunk below it. They may be simple, 
with or without black pigment, or they may have within them 
a reflecting surface. They are best shown in the Myctophide 
and Stomiatide, but are found in numerous other families in 
nearly all soft-rayed fishes of the deep sea. 
The glandular areas may be placed on the lower jaw, on the 
barbels, under the gill cover, on the suborbital or preorbital, 
on the tail, or they may be irregularly scattered. Those about 
the eye have usually the reflecting membrane. 
In all these structures, according to Dr. von Lendenfeld, the 
whole or part of the organ is glandular. The glandular part 
is at the base and the other structures are added distally. The 
' primitive organ was a gland which produced luminous slime. 
