276 THE WORLD OF THE SEA. 
are sometimes deposited singly, but generally in groups, in which 
as many as fifty are now and then found. They are fixed to the 
exterior or interior of an abandoned shell. Each capsule is a 
spheroid, one-fifth of an inch in diameter, supported upon a 
short stem which is fixed to its solid support by an expanded base. 
THE EGGS OF THE ALBIONE UPON A SHELL. 
The envelope of the spheroid is thin; the egg is white or flesh 
coloured, and becomes browner as it approaches the time of the 
hatching. This capsule has no resemblance to the cocoon of 
the fresh-water leeches, which only encloses one egg. The young 
of the albione comes out of the upper end of the egg, but the 
fresh-water leech breaks both ends at the same time. Of the 
reproduction of the branchellion we are still in ignorance. 
