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XII. On the double Organs of Generation of the Lamprey, the 
Conger Eel, the commo?i Eel, the Barnacle, and Earth Worm, 
which impregnate themselves ; though the last from copulating, 
appear mutually to impregnate one another. By Sir Everard 
Home, Bart. V. P. R. S. 
Read February 27, 1823. 
In May, 1806, I was so fortunate as to ascertain that the 
Teredines are hermaphrodites, and that the same individual 
both formed and impregnated the ova. 
In June, 1815 , 1 found the lamprey also to be an animal of 
the same tribe ; and on the present occasion, I wish to ex- 
plain that the conger eel, the common eel, and the barnacle, 
are similar in their mode of generation, every one of these 
animals impregnating itself. 
With respect to eels, I am disposed to agree in the opinion 
of the President of the Society , believing the conger and com- 
mon eel to belong to the same species ; and that the only 
difference between them is the one living in fresh, the other 
in salt water, which will explain the difference in their size 
and colour. 
What renders this probable is, that Sir H. Davy suc- 
ceeded in getting a fresh water eel to live in salt water ; and 
he understands that, after the eel has been accustomed to salt 
water for a year, its colours gradually change, acquiring a 
tint of green. The experiment was carried on in Cornwall, 
and the eel was sent alive, that we might have the opportunity 
