ON A PARASITIC COPEPOD. 87 



Nitocrameira hdellune, nov. gen. et sp., a Copepod of the Family Cantho- 

 caraptidse, parasitic in the Egg-cases of Bdellura. By J. A. Liddell. 

 (Conimnnicated by Prof. G. C. Bourne, D.Sc, F.R.S., F.L.S.) 



(Plates 10 & 11 and Text-figures.) 



[Read 21st March, 1912.] 



Occurrence. 



The specimens from which this description is taken were obtained from 

 Limulus which were kept in spirit for dissection^ in the Department of 

 Comparative Anatomy at Oxford. The precise locality from which the 

 Limulus came is nnknovvn, except for the fact that they were brought from 

 America some twenty-five years ago. 



The gills of Limulus are commonly infested by parasitic turbellarians of 

 the group Bdellurid?3. Wheeler has described three species of these : in the 

 egg-cases of two, Bdellura Candida, Girard, and B. propinqua, Wheeler, 

 which measure 2*5 to 4 mm. and 1"25 mm. respectively in length, a small 

 copepod of the family Canthocamptidse was found, for which I suggest the 

 name Kitocrameira Idellurce. 



With regard to the occurrence of these egg-cases, those of B. propinqua 

 were far more common, and were situated almost exclusively near the bases 

 of the leaves forming the gill-books. Those of B. Candida only occurred 

 rarely and were generally full of eggs, but three empty cases were found to 

 contain the copepod. 



The much smaller cases of Sijncadidum, Wheeler, which are found at the 

 margins of the leaves, never contained any inhabitants. 



The copepod was only found in empty egg-cases, though a certain amount 

 ■of organic debris was generally present, and in one case the remains of a 

 turbellarian embryo were found. 



They only occurred in egg-cases which were comparatively fresh. Older 

 ones, much torn at the opening, or containing particles of sand and inorganic 

 debris, were never occupied. 



The number of copepods in each case varied considerably. One or two 

 were sometimes found, but three to six seemed commoner. Laro-er numbers 

 often occurred, one case containing 23 females and 6 males. 



The number of males and females was approximately equal, the latter 

 preponderating slightly. 



Nauplius and metanauplius stages were also found in the same cases as 

 iheir parents. Very few half-grown specimens were found. 



LINN. JOURN. — ZOOLOGY, VOL. XXXII. 9 



