OYMNOTID^. 141 



Genus 5. GYMNOTUS, Linn. 



Diagn. Skin wholly soft, and entirely destitute of scales. 



Dcscr. One species only is liuown, which resembles the preceding 

 genus Carapus in the general structure of the head, the position 

 of the nostrils, and in the dentition. And as in that, the anal fin 

 leaves but a small portion of the point of the tail free, so in this, 

 the anal extends to the tip of the tail. Head oval, flatly depressed, 

 with tlie opening of the mouth not extending quite so far back 

 as to beneath the eyes, and with broad lips equal to one another in 

 length. Front nostril, a small tube situated in a bell-shaped hollow, 

 sunk above the extremity of the lateral lip ; hinder one placed 

 at the distance of a diameter of the eye, behind and above the 

 front one. Longitudinal and cross rows of pores, lodged in cup- 

 shaped depressions of the occiput ; also a row on the mandible. 

 Lateral line formed of a row of pores placed widely apart. Teeth 

 pointed, numbering about 50 in the upper jaw, and 60 on the 

 mandible. There is, moreover, a second row of six teeth behind 

 the middle of the upper ones ; and along the symphysis of the 

 mandible two short rows, each of two toothlets. Vomer, palate, 

 and tongue, furnished with lateral serratures and orange-yellow 

 cutaneous rolls. Anus situated before the gill-opening, and fur- 

 nished with a small slender papilla. Pectoral and anal fins clothed 

 in a thickish integument, so that their rays cannot be enume- 

 rated. 



20. Gymnotus electricus. 



Gymnotus electricus, Linn. Block, 156 ; Seba, iii. 34, 0. 



Blackish above, whitish below. Variegated blackish markings on 

 the anal fin, which run into longitudinal and cross lines. One 

 can feel through the skin from 334 to 350 anal rays. The species 

 attains a length of from to 9 feet. 



Total length of one specimen . . . . .38-60 in. 



From tip of snout to gill-opening . . . . 3"78 ,, 



the eye . . . . . 0-98 „ 



Width of the mouth 1-73 „ 



From tip of the mandible to the anus . . . 2'92 ,, 



anal fin . . . 7-09 „ 



Length of the pectoral fin ..... 075 ,, 



Breadth of ditto 79 „ 



Height of the gill-opening ..... 0-91 ,, 



Tlie electrical apparatus of this fish is so powerful that it can 

 slay botli men and horses. It is exercised by the will, and directed 

 at the pleasure of the fish, even to a distance, as it kills fish from 

 afar. Yet this faculty is exhausted by continuous employment, 



