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. 



