142 Sir Everard Home on the double organs of 
the use of the microscope to give, upon the same plate, the 
ovarium of the lamprey, and of the conger ; wishing in my 
demonstration of such curious facts, that had escaped the 
accurate observation of John Hunter, they should, as far 
as may be, speak for themselves. 
That species of barnacle, called Lepas Anatifera, has been 
examined, and drawings have been made of it by both these 
great anatomists, Hunter and Cuvier ; but their not having 
met with it in the breeding season, prevented them from 
seeing the manner in which the ova are disposed of, and led 
to considerable error with respect to the organs of gene- 
ration. 
The ovaria are situated round the oesophagus, and may, 
when not met with in the breeding season, be mistaken for 
the salivary glands ; and the penis may be looked upon as 
the oviduct for depositing the ova after impregnation. 
The curious circumstance in this species of lepas is, that 
the ova are impregnated before they leave the ovaria, by the 
point of the penis being bent down and carried for nearly 
one-fourth of an inch into them. After impregnation, the 
ova pass through a small opening in the outer covering 
into the stem by which the body of the barnacle is sus- 
pended ; in that situation the ova are both defended and 
supplied with salt water ; and, when the embryo is completely 
formed, it makes its way out, laterally from the stem, leaving 
behind the shell or covering of the egg attached to the inside 
of the tube, marking the place from which it escaped, the 
young lepas acquiring a stem of its own. In some cases the 
eggs all remain at the root of the stem, and come out ex- 
ternally, just opposite the opening in the outer covering. 
