LlPE-nyCI.R OF "OYSTOP.Ia" IKIIKGULARIS (mINCII.). 8 



case ifc is the ripe cysts, containing spores, wliicli are ex- 

 tremely rare. For this new species I have already proposed 

 (40) the specific name minchinii, after Professor Minchin, 

 in recognition of his earlier work on C. irregularis. 



Since publishing my preliminary note on the trophic 

 phases of C. irregularis and C. minchinii, I have been 

 able to examine the spores of the latter. Mainly as a result, 

 I have come to the conclusion that these two parasites must 

 be separated from the other well-known species (C. holo- 

 thurife), and placed in a distinct genus. The reasons for 

 this step are best reserved, however, until we are in a position 

 to consider a full and revised definition of the two former 

 species (see below, p. 58). Meanwhile, in describing the life- 

 history, confusion will be avoided by retaining the old name 

 of Cystobia for all of them. 



I have also come across Diplocystis schneideri, 

 Kunstler, in a new host, Periplaneta orient a lis. The 

 fortunate rediscovery of this interesting Gregarine has enabled 

 me to compare its trophic phase with that of other known 

 species of the genus, and also with that of Cystobia. 



(1) Introduction. 



For a complete account of the literature relating to 

 Cystobia up to 1892 the reader is referred to Minchin's 

 article (25) already quoted. Since that date I know of no 

 paper dealing with this Gregarine except the systematic 

 enumeration of Labbe (1899). This author, in his SSporo- 

 zoa' (17), gave the characteristics of the genus and its known 

 species, which may be summarised as follows : 



Cystobia, Mingazzini, 1891. — A monocystid Gregarine 

 of large size, oval or irregular in shape. The adult stage 

 always has two nuclei, probably arising from the early asso- 

 ciation of two individuals. Spores with dissimilar poles, the 

 epispore at one end being always turned outwards as a 

 funnel-like projection. Eight sporozoites in the spore. 



(1) C. holothuriEe (Schn.). — Cysts attached to the wall 



