92 W. G. RIDEWOOD AND H. B. FANTHAM. 



half the diameter of the nuclei of the spores. Some of them 

 are surrounded by a clear area of cytoplasm, aud may form 

 spores, but many would appear to be residual, and not 

 destined to give rise to spores. 



The actual transition between the stage of sporulation io 

 a spore-morula and that of residual matter is depicted in 

 fig. 14. The capsule, of which a small part only is shown, is 

 full of ripe spore morulas, aud these are in process of divi- 

 sion into uninucleate spores ; one of them, however, is 

 slightly in advance of the rest, and has already divided into 

 spores, which have scattered, leaving the remains of the spore- 

 morula, pale in colour, with granular protoplasm and remains 

 of nucleus. The outline of this relic (fig. 14, r.sp. m.) in the 

 capsule is more clearly seen than that of its neighbours; its 

 protoplasm is of a light brownish tint, and its nuclear residue 

 of a brownish pink, after staining with hgematoxylin, which 

 imparts a characteristic purple coloration to the neighbour- 

 ing sporulating masses, forming a clear and striking con- 

 trast. 



The remains of spore-morulse, after sporulation, undergo 

 degeneration in old capsules (fig. IC). Their outlines become 

 less distinct, and vacuoles appear in the now coalescing mass 

 of protoplasm (fig. 17). The residual nuclei become less 

 clear, but chromidia may still be seen near the centre of the 

 degenerating mass (fig. 17). Some of the spores, formed 

 from the spore-morulas before they degenerated, may for a 

 time be seen in the neighbouring tissue and in the cavity in 

 which the parent capsule lies (fig. 16). 



While the above account of the life-history of Neuro- 

 sporidium suggests how the infection may spread from one 

 part of the host to another, by the amtebulae and young 

 trophozoites migrating along the course of the nerve tracts, 

 we have no evidence to offer which can explain the spread 

 of the parasite to new liosts. In Bertramia aspero- 

 spora, of Rotifers, the mode of spread has been watched by 

 Bertram ; the spores have no power of independent move- 

 ment, but are disseminated passively on the death aud disin- 



