218 GENERATION 



I then opened many to see if I could discover any spawn, but never 

 succeeded. 



As the lamprey and the lampern have, in some degree, a similarity to 

 the common eel, and as their seasons of propagation are known, I next 

 examined them with the same view when full of spawn, and easily 

 found their parts for propagation 1 , which are somewhat similar to those 

 parts in the common eel, as I had suspected ; and, although not exactly 

 so, yet sufficiently to show the analogy. 



So far encouraged I did not give up the pursuit in the common eel, 

 and was still further encouraged by Sir Joseph Banks, mentioning 

 that when young, he had observed in an eel the roe full of eggs or 

 spawn ; but as he was then not well acquainted with the anatomy of 

 this fish, and only knew there was an uncertainty respecting the mode 

 of propagation, he therefore only preserved a part, and put it into 

 spirit for further examination ; but the spirit evaporating, it dried and was 

 rendered unfit for investigation. Sir Joseph giving me leave to look at 

 some sea-eels caught when on his voyage round the world, in them I 

 found the roe full of eggs, and have since compared them with the 

 common eel, in which I have at last discovered the mode of propagation, 

 which is exactly what I suspected from the structure of the parts. 



On the present occasion it may not be improper to give a short 

 description of the roe in the common roe-fish, with a view to show the 

 difference [between them and the eel] which probably was the cause of 

 its [the mode of propagation in the eel] not being before discovered. 



The roe in fishes in common, or what may be called the ' roed-fish,' 

 consists of two bags ; in some these are long, extending nearly through 

 the whole belly of the animal 2 ; in others they are round 3 , <fcc. They 

 are smooth on the outside ; and on the inside are thrown into a number 

 of flakes or folds, increasing the surface greatly for the form and attach- 

 ment of the eggs or spawn. 



These bags terminate each in a duct near the anus, which ducts join 

 each other, forming one, which enters the anus near the verge, through 

 which the ova pass. 



In both the lamprey and lampern the roes are not bags having the 

 ova attached to the folds on their inside, as in the above described, but 

 are composed of flakes or layers attached at one base along the back, 

 having no cavity. Each flake is composed of two membranes united by 

 cellular membrane, and on the inside of each membrane are the ova as 



1 [Hunt. Preps. Nos. 2658, 2659, 3196-3201.] 



2 [lb. Nos. 2663 (Barbel), 2668 (Mackerel).] 



s [lb. Nos. 2673 (Coitus Scorpius), 2674 (Wolf-fish, AnarrAicas).] 



I 



