278 SOME MINUTE ANIMAL PARASITES 



in certain small animals, known as Cephalodiscus 

 nigrescens, a parasite, Neurosporidium cephalodisci, is 

 found having a general resemblance to Rhino- 

 sporidium and belonging to the same group of 

 organisms. It also has a remarkable distribution 

 in the host, for it is present in the main nervous 

 system, where it causes local degeneration of the 

 nerve tissue, so that in time the parasites lie in oval 

 spaces, wherein they multiply. The partly destroyed 

 nerve matter forms a loose sort of capsule around the 

 parasites. The smallest parasites are like amcebulae. 

 Having reached the nerve cord, they begin to 

 multiply, when they look like irregular masses of 

 protoplasm with two or three nuclei apiece. Several 

 young parasites can be found in one space. Nuclear 

 division rapidly proceeds, and oval bodies with many 

 nuclei are produced. 



A stage follows in which pansporoblasts are formed 

 by protoplasm collecting around each nucleus and so 

 producing a number of small, rounded, uninucleate 

 bodies. The capsule thus becomes full of pansporo- 

 blasts, for they all seem to be formed simultaneously. 

 The pansporoblasts increase in size and the parental 

 material becomes much less. Soon the nucleus of 

 each pansporoblast divides into a number of chro- 

 matin masses which form daughter nuclei. Each 

 nucleus, with the protoplasm surrounding it, is a 

 young sporoblast, and the collection of sporoblasts 

 within the pansporoblast produces the appearance of 

 a mulberry. Each sporoblast becomes a spore with- 

 out much further change. The spores gradually pass 

 out of the cavity around the parent organism, and 



