352 VERTEBRATES: FISHES. 



Fi and anal continued around 



the end of the tail, form- 

 ing by their union a point- 

 ed caudal. The common 

 fresh- and salt-water Eel, 



Eel, A . bostoniensis, LeS. ^ bostOHienSlS, LeS., of the 



United States, is twelve to sixty inches in length. 



The Genus Murcena has no vestige of pectorals. The 

 Roman Muraena, M. helena, Linn., of the Mediterranean, 

 attains the length of thirty-six inches or more, and is 

 mottled with brown and yellowish. This fish was highly 

 prized by the ancients, who fed it in ponds constructed 

 expressly for it. Vedius Pollio caused his transgressing 

 slaves to be flung alive into these ponds as food for the 

 muraenae. The Romans domesticated these eels so that 

 they would approach at call. 



The Genus Gymnotus has the anal fin beneath a greater 

 part of the body, and generally as far as the end of the 

 tail, but no dorsal. The Gymnotus, or Electrical Eel, G. 

 electricus, Linn., of the warm regions of South America, 

 is five or six feet long, and is celebrated for its ability to 

 communicate such electrical shocks that men and animals 

 are struck down by them. 



The Genus Ammodytes has the dorsal fin extending 

 nearly the whole length of the back, the anal long, and 

 both separated from the caudal, which is forked. The 

 species are marine, and live in the sand, and are known 

 as Sand-Eels, or Sand-Launces. 



SUB-SECTION V. 



THE ORDER OF LOPHOBRANCHIATES, OR TUFT-GILLED FISHES. 



THIS Order comprises fishes which have the gills in 

 small round tufts arranged in pairs along the branchial 

 arches, instead of resembling, as in other fishes, the teeth 

 of a comb. 



