22 H. M. WOODCOCK. 



is lateral (i. e. tliat tlie members of a pair originally join side 

 to side after the manner in Gouospora sparsa, Leger 

 [19] ), and not terminal (end to end) as in C. irregularis.^ 

 This arrangement is, of course, masked while the animals are 

 in the trees. 



Trophozoites finally encysted are seen in figs. 15 and 16-; 

 the former of these represents a very large parasite '56 mm. 

 by "43 ram. in diameter, which should rather be termed a 

 sporont, as it was probably ready to begin sporulation. Both 

 individuals show only one nucleus in the section drawn, the 

 other being some sections further on. 



(c) Diplocystis schneideri. 



1 have been able, fortunately, to re-examine this interesting 

 parasite, originally described by Kunstler (16). Although in- 

 cluding an account of it in this paper chiefly for the purpose 

 of comparing neogamy in this form with the same occurrence 

 in other species of the genus and also in Cystobia, I may 

 here indicate wh}^ I thus identify the Gregarines which have 

 come under my notice. The parasites occurred in a single 



' It is interesting to note, in this connection, that Sars (32), so lonq ago 

 as 18G1, figured Gregarines associated in couples and, moreover, laterally, in 

 the Holothurian, Chiridota pellucid a. The parasites apparently adhere to 

 the outside of the blood-vessels, which have here little pear- or flask-shaped 

 diverticula. They appear only loosely attached to each other, with, of course, 

 a distinct wall or partition between the two members, separating the trans- 

 versely-placed nuclei. Judging from the magnification given, their length was 

 about "125 nim. and the breadth 'OG mm. It is impossible to say whether they 

 were adults or not, as this is all Sars describes of the parasites. In "pairing" 

 side-to-side, and in being apparently free iu the body-cavity (i hey do not seem 

 to be attached by any stalk to the vessel, i. e. to have evaginated its wall), 

 they exhibit a certain resemblance to C. minchinii; the association would 

 appear, however, to be much less intimate iu character. It wouki be very 

 interesting if these Gregarines could be re-discovtred in Chiridota. 



2 The irregularity in outline at times shown, unfortunately, by these 

 encysted stages (e. g. fig. 15) is due to the difficulty I eXj)eriencod in fixing 

 them, owing to tiie thick connective-tissue layer through which the fixative 

 had to penetrate. Corrosive sublimate, well sharpened with acetic acid, served 

 best. 



