On the double organs of generation of the lamprey , &c. 141 
of judging for ourselves ; but it never arrived in London. He 
began with young small eels, which all died ; when however 
he took one of a tolerable size, it seemed to suffer little incon- 
venience. 
The organs of generation in the conger and common eel are 
exactly similar ; and I have been so fortunate, on the first 
of February, 1823, to receive a conger from Plymouth, with 
ova distinctly visible in the microscope, and the structure of 
the testicles equally apparent. Out of three congers sent to 
me, this state of the ova was only met with in one, so that 
they do not breed regularly in the same month. As this has 
not, I believe, been noticed before, I got Mr. Bauer to re- 
present the parts in the annexed drawing, and thought it 
might be satisfactory to the Society to see a magnified draw- 
ing of these double organs in the lamprey, where they are 
brought closer upon one another by the absence of an air 
bladder, on the sides of which the ovaria of the common 
eel and conger are spread. 
In the eel tribe the kidneys are immediately behind the 
peritonseum, and so closely connected with the testicle, when 
the eels are not caught in the breeding season, that the . 
whole mass has been taken for kidney ; and had I not been 
favoured with the assistance of Mr. Bauer and Mr. Clift, 
I might have failed in procuring such accurate and distinct 
representations of these parts. 
Mr. Clift, upon a former occasion, made a drawing of the 
testicles and ovarium of the lamprey, in which the parts were 
only sufficiently enlarged to identify the facts they were in- 
tended to demonstrate. I have now, to establish them more 
completely, taken advantage of Mr. Bauer's superior skill in 
