NEUROSPORTDIUM. 93 



tegration of the body of the host.^ Possibly the same may 

 happen in the present instance. 



Systematic position of Neurosporidium. 



In determining the systematic position of Neurospo- 

 ridium ceplialodisci the following features in the life- 

 history, so far as we have been able to trace it, should be 

 kept in view : 



1. From a capsule lying in a cavity in the nervous system 

 of Cephalodiscus gymnospores or amasbulag are liberated, 

 as rounded masses of clear, naked protoplasm, 2 to 4 fi in 

 diameter, eacli with a centrally placed nucleus, 



2. The next stage is one in which a small multinucleate 

 trophozoite lies in a small cavity in the nervous system. 

 This stage is reached, either by the r.ipid growth and nuclear 

 division of a single amtebula, or by the coalescence of several 

 amaebulae (plasmodium). 



3. Nuclear division of the trophozoite continues, and the 

 size increases, until the body is about 30 to 50 fx in diameter, 

 and ovoid in shape. The general protoplasm is granular and 

 opaque, but there is a clear zone of protoplasm around many 

 of the large nuclei. 



4. The large ovoid trophozoite segments into pansporo- 

 blasts, each a single cell, 3 to 5 /x iu diameter, consisting of a 

 large nucleus surrounded by clear cytoplasm. 



5. The nucleus of each pansporoblast divides into many 

 daughter-nuclei, and the pansporoblast enlarges and becomes 

 a spore-mornla, 10 to 15 fx in diameter. Each daughter- 

 nucleus, with its small mass of clear cytoplasm, becomes a 

 sporoblast, and then a spore. The spores are generally dis- 

 tributed throughout the spore-morulse. 



6. The spores ultimately separate, and pass out into the 

 adjacent parts of the nervous system of the host. The remains 

 of the spore-moruh\3, consisting of granular protoplasm, pale- 

 staining remains of nuclei, and some free chromidia, undergo 

 gradual degeneration. 



' Caullery and Mesnil, loc, cit., p, 136. 



