APODAL SOFT-FINNED FISHES. 



345 



as well as rivers. By day they almost always keep buried in the 

 mud, or lie concealed in holes that they excavate near the shore. 

 These holes are sometimes very extensive, and lodge a great number 

 of eels ; but in general their diameter is small, and they open ex- 

 ternally at both ends, thus enabling the animal to escape more 

 easily when threatened with danger. When the season is very 

 warm, and the stagnant waters of the pool begin to putrify, the eels 

 leave the bottom and conceal themselves in the herbage of the shore, 

 or even cross the land in search of a more favourable locality ; they 

 can, in fact, crawl on the ground like serpents, and remain a con- 

 siderable time out of the water without perishing. Ordinarily they 

 make these singular journeys during the night. When the ponds 

 dry up they bury themselves in the sand and remain there till 

 the water returns. The length of time they can remain in such a 

 situation without perishing is surprising. In early life, eels inhabit 

 the sea, and in the spring the young eels ascend rivers to dwell in 

 fresh water, which, when full grown, they abandon to deposit their 

 eggs in the sea. 



The Conger Eels differ very little from common eels, except that 

 they are of larger size, and always live in the sea or salt water. 



FlG. 277. CONGER EEL. 



The Mursenae (Mursena) are entirely destitute of pectoral fins, and 

 their branchije open on each side by a small hole. The most 

 celebrated species is Mursena helena, which attains nearly three feet 

 in length, and is marbled with brown and yellow. It is widely 



FlG. 278. MUR^EN^E. 



spread through the Mediterranean, and was very highly esteemed by 

 the ancients. The Romans reared them in great numbers in their 

 magnificent fish-ponds, decorated them with jewels, and taught them 



Q 3 



