2 H. M. WOODCOCK. 



ably devote a portion of my time as Derby Scholar in endeavour- 

 ing to obtain fnrtlier stages in tlie life-history of Cystobia 

 (Gregarina) irregularis. This Gregarine, which is para- 

 sitic in Holothuria forskali,i the " cotton-spiuner " of our 

 South- Western coast^ was originally described by him (25), 

 but, in view of the recent important advance in our know- 

 ledge of the life-cycle of many Gregarines, it appeared 

 desirable to try and ascertain more fully to what extent 

 Cystobia agrees with, or diverges from, other members of 

 the order. 



I applied for, and obtained, the use of a British Associa- 

 tion table at Plymouth, which I occupied in the spring and 

 again during the summer of 1902. Some of my time, how- 

 ever, was taken up with other Sporozoau work. Apart from 

 '^ free " or unencysted parasites, which were usually examined 

 fresh, most of the material collected was preserved at once in 

 different wnys and cut, stained, and examined either there or 

 on my retumi to University College, where all the drawings 

 were made. 



I experienced, unfortunately, great difficulty in procuring 

 the hosts, especially in the spring and early summer, when 

 some very important stages in the life of the parasite are 

 undergone. Only too often, moreover, the animals, when 

 obtained, were found to be uninfected. Nevertheless, I have 

 been successful in learning many interesting additional facts 

 with legard to this species of Cystobia — sufficient to 

 enable me to give a fairly complete account of its life-cycle. 

 In addition, I have found another Gregarine, inhabiting 

 Cu cum aria pent act es and C. planci, which shows marked 

 peculiarities in its habitat and trophic life and is certainly a 

 distinct species. Owing to the even greater scarcity of this 

 parasite I am unable, in spite of great efforts, to give an equally 

 complete description of this new form. Wiiereas in C. irreg- 

 ularis, the trophic stages are the more uncommon, in this 



' This species is generally known as H. nigra, Kinalian, but Koeliler (15) 

 stales tliat it has been shown to be identical wilh H. forsk&li, De C, and 

 that the latter name takes priority. 



