PISCES. 119 



Stemarchus SCHN. Body compressed, scaly; head naked. 

 Caudal fin distinct, separated by an interval from anal. Anal fin 

 Beginning from throat, with vent placed under the throat. Mem- 

 branous cirrus in back, affixed by tendinous filaments. 



Sp. Stemarchus albifrons SCHN., Gymnotus albifrons L., PALL. Spirit. Zool. 

 vn. Tab. vr. fig. i ; Stemarchus oxyrhynchm MUELL. and TROSCH. Hor. 

 Ichth. ill. Tab. 2 ; in South America, like all the species of this family. 

 There are two groups of conical teeth in the intermaxillary bone, and two 

 rows of similar teeth in the lower jaw. 



Carapus Cuv. Body depressed, scaly; head naked. Anal fin 

 )roduced as far as the apex of tail, attenuated, and without dis- 

 tinct caudal fin. 



Sp. Carapus Carapo, Gymnotus Carapo L., BLOCK Ichth., Tab. 157, fig. i, &c. 



Carapus rostratus, Gymnotus rostratus L., BLOCH Syst. Ichth. Tab. 106 ; 

 the mouth is without teeth, at the end of an elongated snout, narrow at its 

 termination. MUELLER and TROSCHEL form from this species the sub-genus 

 Rhamphichthys. There are only three rays in the gill -membrane, whilst 

 the other species have five. 



Gymnotus Cuv. (spec, of Gymnotus L.). Body round, with in- 

 distinct scales. Tail truncate, with caudal fin conjoined with anal. 



Sp. Gymnotus electricus L., BLOCH Ichth. Tab. 156, Cuv. R. Ani., td. ill., 

 Poiss. PL no, fig. i ; the electrical eel, PAnguille electrique. This species 

 lives in fresh water, in ponds, &c. in South America, and attains the consider- 

 able length of more than five feet. The electric organs comprise two larger 

 above, and two smaller below, and are situated on each side of the body, 

 occupying about three-fourths of its length ; the large organs lie immedi- 

 ately under the skin, the inferior are covered by the muscles of the anal fin. 

 The apparatus is formed by membranous, aponeurotic partitions, which run 

 in the length of the body almost parallel to each other, and between which 

 extremely fine transverse plates are situated, thus forming small chambers 

 filled with fluid. The nerves which run to the electric organs are not here, 

 as in Torpedo a,ndMalapterurus(see above, pp.64, 89), branches of cerebral 

 nerves, but branches of spinal nerves, of more than two hundred pairs of 

 nerves, which for the most part also give branches to the swimming-bladder. 

 The shocks are subject to the will of the animal ; by repetition of them the 

 fish loses for a time the electric power ; hence, in order to capture these 

 electric eels more easily, wild horses are sometimes driven into the water, 

 and exposed to their first attacks. 



Compare J. N. S. ALLAMAND Verhandelingen van de Haarl. Maatschap- 

 pij, IT. 1755, bl. 352 379 ; J. HUNTER An Account of the Gymnotus elec- 

 tricus, Phil. Trans. Vol. 65, Part 2, 1775, pp. 395 407, or in the collec- 

 tion published by R. OWEN, of his Observations on certain parts of the 



