330 PLAGIOSTOMATA. 



Family VII TOKPEDINIDiE. 



Trunk broad and disk smooth. Anterior nasal valves confluent and forming a 

 quadrangular flap. Tail with a rayed dorsal (except in Temera) and caudal fin, 

 also a longitudinal cutaneous fold along either side. An electric organ situated 

 between the pectoral fin and the head. 



The electric organs of these rays are somewhat kidney-shaped, one being 

 placed on either side of the body, occnpying its thickness, and circumscribed by 

 the pectoral fin, the head, and the gill cavity. They are comprised of many hexa- 

 gonal or pentagonal prisms, each of which is divided into cells by transverse 

 membraneous subdivisions, and these cells contain a trembling, jelly-like, fluid 

 substance. These prisms are placed perpendicularly to the dorsal and ventral 

 surfaces of the fish. Each electric organ receives a large branch of the fifth 

 pair of nerves, and four branches of the vagus division of the eighth pair. It has 

 been asserted that when a shock is given it moves its pectoral fins convulsively, 

 that the convex part of the upper surface becomes gradually depressed, and subse- 

 quently the convexity suddenly returns. Should the torpedo be on a metallic 

 plate, so that its ventral surface touches the metal, the hand which supports the 

 plate does not feel any shock, even although another insulated person may excite 

 the animal. By passing the discharge throug'h a spiral of copper wire enclosing 

 a steel needle, the needle becomes magnetized in such a manner as to show the 

 direction of the current to be from the dorsal to the ventral surface. 



The electrical powers of this fish diminish as its strength decreases, while the 

 presence of this property does not deteriorate from the use of its flesh as food ; 

 in fact, in the time of Galen, its flesh was recommended to be eaten by epileptic 

 persons, who were likewise to have shocks from the living fish applied to their 

 heads. Even prior to this time, Dioscorides had recommended its external appli- 

 cation for pains in the head. In more recent times persons suffering from gout 

 were advised to place the affected part on one of these fish, and keep it there until 

 the numbness extended as high up as the knee. This electric power serves to 

 assist these fishes in obtaining food, as they benumb their prey ; while the same 

 power protects them from their enemies. Plutarch mentions that their numbing 

 influence has been known to pass from the net to the fisherman's arms ; and Pliny 

 that it can be conveyed along a stick or other substance. 



An old writer (quoted in the "Anglers' Note Book," p. 151) remarked that 

 " Gaianus affyrmeth, that he who dippeth his hande into licor of Cyrenaicum doth 

 turn to nought the power of the Torpedo, and may touch him unharmed." 



These fish are said to be sluggish, and conceal themselves in sand and mud, 

 where they lie in wait for passing prey. But little is known of their habits. 



Genus I Torpedo, Dumeril. 



Narcobatis, Blainville : Narcacion, Bleeker. 



Disk distinct from the tail, which has a lateral cutaneous fold along either side. 

 Spiracles a short distance behind the eyes. Nasal valves confluent, forming a quad- 

 rangular flat. Teeth small, conical, and pointed. Tivo dorsal fins on the tail portion 

 of the body, and both destitute of spines. Caudal fin well developed. An electric 

 organ situated between the pectoral fin and the head. Shin smooth, and destitute of 

 spi?ies. 



Although Pennant figures and describes Torpedo marmorata as the only 

 British form, he does not distinctly state whether his specimen was not one brought 

 by Walsh from France. It is true he alludes to two British examples, but it is 



