378 ^^y- n. A. l^nylis oh Inhahitanis of 



XXXTII. — A ritrafiiti'c Olifjochfelc, and othci' Tnhah'itanh of 

 the Gill-chamhers of Land-crahs. By 11. A. BayliS, B.A. 



(Publiished by permission of the Trustees of the British Museum.) 



A SMALL Oligoclioete worm of tlie fiimily Encliytrfcidfip occurs 

 frequently in consideralile iiunibers in the iiill-clianibers of 

 the crab Ge'-arcniuH lagostoma in the island oi South 

 Trinidad. Having been enjraged in the study of this species, 

 for -whirli I have proposed the name Enchytranis cnrcino- 

 jiliilus [2], it occurred to me that it might be of interest to 

 examine the gill-chambers of other crabs of the family 

 Gecarcinidre, with a view to finding out whether they 

 harboured any further Oligochaites or other parasites. 



Tiuongh the kindness of Dr. W. T. Cahnan, I was able 

 to examuie specimens in the British Museum bearing the 

 following names: — 



Cardisoyna guanhumi, 



hirtipes. 



armatum. 



carni/e.r. 



sp. ? (Lagos, W. Africa). 



Ucides cordatiis. 



occidental is. 



(jrccarcinus lateralis. 



ruricola. 



quadratus. 



(jr( ca rcoidea Jalandii. 



The results of this investigation were as follows: — 



Orgatiisms which may possibly be regarded as ])arasit(s 

 were found in only three ot the eleven species above named, 

 viz. : — Cardisonia hirtipes, Gecarcimis quadratus, and Gecar- 

 coideu lalaJidii. In Gecarcinus quadratus were found very 

 numerous examples of a small Eiichytiasid worm, which 

 proves to be specifically distinct from that already recorded 

 as occurring in G. lagostoma, and which will be described 

 below. 



In Cardisoma hirtipes and Gecarccidea lalandii the 

 creatures found proved to be dipterous larvse of two distinct 

 species, though it was found impossible to determine them 

 precisely. 



\ 



