THE TRUE FISHES. 



173 



Lamp-Fishes (Sfarmatid&). In these and allied fishes 

 the skin is naked, or the scales extremely minute, and 

 nearly all have organs that look like pearl or glass buttons 

 imbedded in the skin. According to Leydig, they are of 

 three kinds : first, eye-like organs ; second, pearly, glass- 

 like organs ; and, third, luminous organs. According to 

 different authors, they are eyes, electric or light-giving 

 organs. Gunther considers them all luminous, and that 

 their function is to light the dark recesses of the submarine 

 world. 



In the Stomias the pearly spots are along the ventral surface, a 

 veritable row of glowing lights. Allied to the Stomias is the lamp- 

 fish (Scopelus) \ upon its head" is a soft prominence that glows like a 

 head-light. Willemoes-Suhm says, " One of them hung in the net 

 like a shining star." Other phosphores- 

 cent spots are scattered along the lower 

 surface of Scopelus Httmboldti and Be- 

 noitii (Fig. 216). Another allied form 

 is the Bombay duck or Harpcdon (Fig. 

 216), that is luminous over its entire sur- 

 face. The eyes of Ipnops are adapted 

 for receiving and perhaps emitting phos- 

 phorescent light, and a curious phos- 

 phorescent organ is found upon the head. 

 Several species of the genus Echiostouia 

 live in Australian seas at a depth of two 

 and a half miles. They are black, with 



long, fringed barbels, and below the eyes and in other places are 

 several luminous spots. The Bathyophis ferox lives at a depth of 

 nearly three miles, the greatest depth attained by any fish. It has 

 long barbels or feeler?, and rows of gleaming lights on its various 

 parts. Allied is the Chanlijdus (Fig. 216, i). The tips of the fins 

 are luminous, while a row of luminous spots extends the entire length 

 of the body. The little fishes Argyropelecus (Fig. 217) and Ster<- 

 noptyx arc found in the Mediterranean. The body is extremely deep, 

 rising suddenly and narrowing off to the tail. The luminous spots are 

 in groups from the head to the tail. Perhaps allied to this group is a 

 strange fish (Fig. 218) about twenty inches in length, with a pouch-like 

 mouth and no fins, found in water over a mile deep in the Mediter- 

 ranean, and also dredged oft the American coast. It differs from all 

 13 



FIG. 215. Luminous organ 

 from side of Scopelus 

 (1 ig. 216, 8;. 



