236 APO'DES. 



no knowledge. The mud-eel is exceedingly com- 

 mon. Perhaps there is no one fish, the genera- 

 tive process of which has given naturalists more 

 vexation than this ; hence the old and vulgar no- 

 tion that there was no distinction of sex, and that 

 they originated spontaneously from the mud. Let 

 it be understood, however, that modern persever- 

 ance has settled the question, as the males can 

 readily be distinguished from the females. They 

 are viviparous, and are impregnated as all carti- 

 laginous fishes are. * 



That the eel is wonderfully tenacious of life, 

 has become a proverb, live as long as an eel. 

 Hours after being deprived of the skin, as may be 

 daily noticed in the market, they continue to ex- 

 hibit violent and rapid contortions. 



In the year 1803, the water from an overflown 

 quick-silver mine, at Idua, in Austria, having been 



* Male crabs may be distinguished from the females by the 

 organization of the flap or apron, on the breast of both, and 

 yet this has been a long disputed point, like the quarrel about 

 the sex of eels. That on the female is large, loose, broad and 

 easily opened when the animal is alive. On the male, it is 

 smaller, firmer, and less easily opened ; under it are two 

 thread-like organs, but in the female there are two orifices, 

 tipped with cartilaginous rings. En Vunion sexuelle, IKS ft- 

 melles conchies sur leurs dos r6coivent ces excroissances fili- 

 formes dans les deux ouvertures ou 'vulva. This is the only 

 example within our knowledge, of a double piocreative appa- 

 ratus. 



