NEUROSPORIDIUM. 81 



On Neurosporidium cephalodisci, n. g., n. sp., 

 a Sporozoon from the Nervous System of 

 Cephalodiscus nigrescens. 



By 



W. G. Kidewood, D.Sc, 



Lecturer in Biology at St. Mary's Medical School, University of Loudon ; 



AND 



H. B. Faiitliaiii, B.!§<'., A.R.C.S., 



University College, London ; Demonstrator in Biology at St. Mary's 

 Medical School. 



With Plates 6 and 7. 



Introduction. 



The organism described in this paper occurs in the 

 nervous layer of the ectoderm of Cephalodiscus (Idio- 

 thecia) nigrescens, Lank., a large and massive form of 

 Cephalodiscus dredged by the " Discovery " on January 

 ISfch, 1902, in 100 fathoms, off Coulmann Island, near 

 A^ictoria Land, in the Antarctic Ocean. 



The specific name nigrescens was given to this Cephalo- 

 discus by Prof. Ray Lankester,^ the polypides being to the 

 naked eye of a sooty black colour ; a detailed description of 

 the polypides and the tubarium or "house" of Cephalo- 

 discus nigrescens is given in the " Reports of the 'Dis- 

 covery ' Expedition," published by the British Museum. 



The Sporozoon that occurs in Cephalodiscus uigres- 



1 ' Proc. Roy. Soc.,' 1905, pp. 400—402. 

 VOL. 51, PART 1. NEW SERIES. 6 



