100 NUDIBRANCHIATA. 
therefore, to pass through a metamorphosis before 
it attains its permanent condition. 
The eggs in all the species are numerous. 
They are deposited, during the spring and summer, 
LARVA OF EOLIS. 
commonly in the form of a broad ribbon of clear 
jelly, attached by one of its edges to some solid 
substance, and generally coiled, or irregularly 
twisted, or frilled. The eggs themselves are 
arranged in close-set rows, crossing the gelatinous 
belt, and giving an opaque white appearance to the 
mass, which would otherwise be colourless. 
In general each egg-shell (chorion) contains but a 
single yolk, but in some of the Dorides each con- 
tains two or three; and in the elegant Antiopa 
cristaia, a specimen of which lately spawned in 
my possession, I found, upon the average, the 
extraordinary number of sixty yoiks in each egg 
shortly after deposition. The yolk, which is con- 
tained within a delicate, transparent, membranous 
