WHAT A NOSEMA SPORE CONTAINS 223 



the progress of events going on within is quite 

 obscured. When the sporoblast has only just begun 

 to form the coat, the protoplasm gradually concen- 

 trates at one end of the spore, and as a result a 

 vacuole, or space, containing liquid appears at one 

 end. This end is known as the posterior or hinder 

 end of the spore, and the vacuole is called the 

 posterior vacuole. Later, a second vacuole, with 

 much firmer limits or boundaries to it, appears at 

 the anterior end of the spore, and this second one 

 is known as the polar capsule (Fig. 41, A, D). 

 From the now girdle-like contents of the spore 

 henceforth known as the sporoplasm (Fig. 41, 

 C, D, E) a long strand of protoplasm with an 

 elastic core is formed, and this coils up within the 

 posterior vacuole and polar capsule, and is known 

 as the polar filament. Under certain circumstances 

 this thread can be ejected through the polar capsule 

 with considerable force, and so anchor the spore to 

 the epithelium of the alimentary tract. 



Not only are there these changes in the sporo- 

 plasm, but great changes go on in the nucleus as 

 well. The original nucleus has many potentialities, 

 which now manifest themselves. The nucleus first 

 divides into two, each daughter nucleus with a 

 different destiny (Fig. 41, A). One of the two 

 nuclei separates from the other, and again divides 

 into two. Each of these nuclei becomes lengthened 

 and threadlike (Fig. 41, C, E) and moves away to 

 the edge of the spore. They control the growth of 

 the sporocyst, which now grows far more rapidly 

 than before. At the same time, the second of the 



