437 



accompanying the specimens that the spores were almost constantly 

 14 fi in length by 4 ^t in breadth, the extreme range being from 12 to 

 16 II in length and from 3,5 to 5 u in breadth; that the ends tapered to 

 a blunt point, and that at each end was situated a deeply stained polar 

 capsule; that the spore-coat was markedliy striated; and that the para- 

 sites did not appear to excite any reaction in the tissue of the host , the 

 animal's health being unaffected. 



The tissue was not very well preserved, but the main features could 

 be made out fairly satisfactorily. The largest specimen of an individual 

 myxklium measured 160 a in length by 27 /< at its broadest part (Fig. 7). 

 In the majority of instances no distinction between ectoplasm and en do- 

 plasm could be drawn, but in a few in which almost the whole animal 

 was converded into spores there was some appearance of a cuticle or 

 cyst-vall (Fig. 8). The protoplasm contained a large number of nuclei, 

 apparently of two varities some vesicular, others smaller and solid- 

 looking. It was difficult, however, to make sure that the latter were 

 not merely granules , of deeply-stained material. Two forms of nuclei 



Fig. 8. Fjg 9. 



_.#*^-"----^„, Fig. 10. 



Fig. 8. Portion of myxidiimi , almost completelj" converted into spores, showing 



thickening of cuticle at upper part. 



Fig. 9. Portion of myxidiuiii in section, showing 2 sporoblasts in a cavity. 



Fig. 10. Dispoi'oblast showing 10 nuclei, one of which is dividing {?). 



are described by Schröder in Sphaeromyxa labrasesl, in which con- 

 junction, but not conjugation, takes place between a large and a small 

 nucleus as a preliminary to sporulation. 



Spores are formed in pairs , at many points within the 7n//xidmm 

 simultaneously. Ultimately almost the whole substance of the animal 

 is converted into spores (Fig. 8). With but limited material in this case 

 also, only a few stages in the development of the spores could be ob- 

 served. A portion of protoplasm becomes rounded off and lies in a 

 definite space within the parasite (Fig. 9). This portion (disporoblast?) 

 contained in one instance 10 nuclei, of which one was possibly dividing 

 (Fig. 10). The final sporoblasts into which this divides appear to contain 

 usually 6 nuclei (Fig. 9), so that it seems likely that 12 is the full number 

 of nuclei in the disporoblast; but the sporoblast depicted on the right 

 hand in the figure (which had been broken in making the section) appears 



