A. E. Verrill — Decapod Crustacea of Bermuda. 323 



Sex 



The proportion of length to breadth of the carapace varies from 

 1:1.25 to 1:1.41, but is usually about 1:1.30 to 1:1.35. 



A parasitic isopod crustacean sometimes infests its branchial 

 cavities and in some cases causes an enlargement or distortion, due to 

 the swelling of the cai'apace on one side. The parasite, which is allied 

 to Bopyrus and Cepon, is relatively large.* It occurred in about 25 per 

 cent, of the adult specimens examined from some localities. Some 

 of the specimens collected in April carried eggs. Some were then 

 soft-shelled. Specimens collected in June and July (Berm. Biol. Sta.) 

 also carried eggs. 



This appears to be the most abundant shore crab at Bermuda. It 

 is to be found everywhere between tides where there are loose stones 

 or masses of dead alg© under which it can conceal itself. It is also 

 to be seen running actively about in such localities, where it is often 

 associated with /Sesarma JRlcordi and Planes minutus. 



It is sometimes found, also, on the coral reefs. Also among the 

 roots of mangroves. 



It has been taken in Bermuda by nearly ever3^ collector of Crus- 

 tacea. 



It has a very wide distribution in all tropical and subtropical seas. 

 It has been found among the barnacles, etc., scraped from the bot- 



* These parasites have recently been sent to Miss Harriet RichardsoTi, who 

 identifies them as Leiclija distorla {Cepon distorta Leidy). It was originally 

 found in the gill-cavity of a " fiddler-crab " (Gelasinius pugilator) by Leidy on 

 the coast of New Jersey. It has seldom been found by later collectors. 



