MUR.ENIDJE, OR EEL-TRIBE. GTMNOTID.E. 75 



637. In the MURJENID^E, or True EeJs, the upper jaw is 

 formed solely of the intermaxillary bones, and the branchial 

 apertures are placed on the side of the head. The ordinary Eels, 

 of which there are several species, inhabit ponds, rivers, and the 

 brackish water at the mouths of rivers. In the autumn they make 

 their way to the sea in vast numbers ; for the purpose, it is be- 

 lieved, of depositing their spawn. Myriads of minute Eels, 

 three or four inches long, are seen in the spring, making their 

 way up rivers, and dispersing into the tributary streams as 

 they proceed ; but whether the parent Eels thus return is un- 

 certain. It is well known that the Eels which inhabit inland 

 lakes and ponds, whence they cannot escape to the sea, are able 

 to breed without this migration ; but it appears that their season 

 is somewhafc later, the water in such situations being colder than 

 that of the sea in the early spring. Eels frequently quit the 

 water, in warm, damp nights, and wander over the grass ; either 

 in quest of worms, frogs, or other food ; or in order to change 

 their locality. Many of this family are chiefly marine ; though 

 they occasionally stray into the mouths of rivers ; this is the 

 case, for instance, with the Conger, which is one of the largest 

 of the whole group, sometimes measuring six feet in length, and 

 being as thick as a man's leg. The Ophisurus, or Snake Eel 

 (so called from its strong resemblance to a serpent) of the Medi- 

 terranean, attains the same length, but is not so thick. In the 

 genus Murcena, and its allies, the pectoral as well as the ventral 

 fins are wanting; and the gill-openings are extremely small. 

 This, too, is a Mediterranean fish ; it was much esteemed by the 

 ancients, who kept it carefully in ponds ; and there is a well- 

 known story of a cruel master, who caused his offending slaves 

 to be flung alive into the ponds, to feed the Muraenae. The com- 

 mon species grows to the length of three feet or more ; its sur- 

 face is mottled brown and yellow ; and it is very voracious and 



638. The GYMNOTIDJE, or Electric Eels, have been separated 

 from the preceding family on account of the less complete in- 

 closure of the gill-covers by the skin, and the structure of the 

 upper jaw, which is partly formed by the maxillary bones. The 



