378 Mr. H. A. Baylis on Inhabitants of 



XXXIII. — A Parasitic OligochcBte, and other Inhabitants of 

 the Gill-chambers of Land-crabs. By H. A. Baylis, B.A. 



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



A SMALL Oligochsete worm of the family Encliytrgeidse occurs? 

 frequently in considerable numbers in the j:>ill-chambers of 

 the crab Gerarcinus lagostoma in the island of South 

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

 for which I have proposed the name EnchytrcBUS carcino- 

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

 examine the gill-chambers of other crabs of the family 

 Gecarcinidse, with a view to finding out whether they 

 harboured any further Oligochfetes or other parasites. 



Through the kindness of Dr. W. T. ('alman, I was able 

 to examine specimens in the British Museum bearing the 

 following names : — 



Cardisoma guanhumi. 



hirtipes. 



armatum. 



cannifex. 



sp.?"( Lagos, W. Africa). 



Ucides cor data s. 



occidentalis. 



Gecarcinus lateralis. 



ruricola. 



quadratus. 



Gecarcoidea lalandii. 



The results of this investigation were as follows : — 



Organisms which may possibly be regarded as parasites 

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

 viz. : — Cardisoma hirtipes, Gecarcinus quadratus, &.x\^ Gecar- 

 coidea lalandii. In Gecarcinus quadratus were found very 

 numerous examples of a small Enchytigeid 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 Gecarcoidea lalandii the 

 creatures found proved to be dipterous larvae of two distinct 

 species, though it was found impossible to determine them 

 precisely. 



