£68 Sir Everard Home on the mode of generation 
that gland, while the tubular bodies which project into the 
cavity of the abdomen, and are increased to double their 
usual size at the time of shedding the eggs, must be consi- 
dered as the testicles. 
The ova in the lamprey do not pass out at an excretory 
duct as in fishes, but drop from the cells in the ovarium in 
which they were formed into the cavity of the abdomen, and 
escape by two small apertures at the lower part of that cavity 
into a tube common to them and to the semen, in which they 
are impregnated. 
This mode of impregnation is so much more economical 
than that employed in fishes, that it explains the circum- 
stance of the testicles being so small. 
In the animal, intermediate between the lamprey and myx- 
ine, and in the myxine, the organs of generation have the 
same structure as in the lamprey. 
EXPLANATION OF PLATE XIV. 
Fig. l. A lamprey of the natural size laid open, to show 
the ovarium at the time the eggs begin to be shed, some of 
them lying loose in the cavity of the belly, others remaining 
in the cells of the ovarium in which they were formed. 
On each side of the ovarium is seen a glandular body pro- 
jecting into the cavity of the belly, which I have explained to 
be the testicle. It is made up of tubes placed in a transverse 
direction; behind it is a substance composed of a reticular 
