BOPYRUS. 217 
The females observed by him were five lines, and the 
males a line and one-third long. ‘The former were in- 
variably found upon female prawns, of which he had 
observed several hundreds thus infested, whilst quite as 
many male prawns which he had observed were found to 
- be free from their attacks. 
The mode of attachment of the parasites and the various 
and peculiar species of crustacea on which they subsist is 
worthy of some consideration. 
They apparently work in pairs and only so, and from 
the following isolated observation would seem to do so 
from their earliest stages. 
Some little time since, having been requested to 
examine some crustacea brought home from Australia, 
we found a shrimp (Caridina truncifrons*) laden with ova, 
amongst which we perceived two specimens of the larva 
of a Bopyroid crustacean, a circumstance that appears 
to throw some light on the subject, by suggesting the 
supposition that the larval Bopyri first take shelter among 
the freely hanging ova previously to their finding their 
way beneath the branchial walls of the carapace, and so 
having quitted the care of their own parent, they are 
fostered by another, on whom probably at a later period 
they prey parasitically. 
* Proc, Zool. Society, Nov. 24, 1863. 
