OBSERVATIONS ON THE GREGARINES OE HOLOTHUEIANS. 301 



CuENOT (4) places the three known to him in the genus 

 Syncystis, Aime Schneider, namely, S. synaptse from the 

 intestinal vessel and coelora of Synapta inhserens; S. ho- 

 lothuriae, Ant. Schn. sp., from Holothuria tubulosa; and 

 S. Miilleri from ccelom of Synapta digitata. He does 

 not appear to be personally acquainted with "Syncystis 

 holothurise/' or with the fact that it had been described as 

 binucleated by Kolliker and Schneider, or he would certainly 

 not say it was similar to the form he describes, more espe- 

 cially " Syncystis synaptae" (= Monocystis synaptse, 

 E. R. L,), in which we may note from his description the 

 following points : — a doubly contoured cuticle ; a single nu- 

 cleus ; cyst limited by a cuticle like that of the Gregarine, 

 with in the centre a spherical nucleus de reliquat (a quite 

 unusual use of the terra, which is always applied to unused 

 matter in the spore) ; spores oval or navicular, with three or 

 even four nuclei. In a foot-note we are informed that Pro- 

 fessor Aime Schneider had considered this form as belonging 

 to the genus Urospora. Professor Biitschli also wrote to 

 me " Ein Schwanzanhang der Sporen ist von der Gattung 

 Urospora, Aime Schneider bekannt, es scheint daher wahr- 

 scheinlich, dass die Gregarine der Holothuria zu dieser 

 Gattung gehort." Mingazzini (5), on the other hand, places 

 them in the family Syncystidse, but establishes a new genus 

 Cystobia for them, considering that they differ from the 

 genus Syncystis, in which the spores have at each pole four 

 diverging bristles (setole), while in the genus Cystobia the 

 spore has only two bristles, and only at one pole. The genus 

 Cystobia is characterised as follows : — '' Lives conjugated in 

 special cysts formed in the tissues, especially in the walls of 

 the vasi acquiferi. Cysts proper with the wall covered 

 with little spines. Sporulation complete. Spores very nu- 

 merous, fusiform, bicaudate, with three falciform bodies.'^ 

 As we have seen, almost the only details in this diagnosis 

 which are correct are " sporulation complete, spores very 

 numerous." In this genus the author puts two forms, Cys- 

 tobia holothuriee, Ant. Schn., and a new species, Cystobia 



