N. H. SWELLENGREBEL 
355 
These individuals, rich in nuclear inaterial, will produce the sporo- 
blasts and consequently are to be considered as pansporoblasts. Their 
protoplasm does not stain so deeply as that of the trophozoites but it 
has a similar alveolar structure. They have a diameter of 4<'9-6‘3 (jl. 
The formation of the sporoblasts is represented in Diagrams IX 
and X. 
(c) Formation of the sporoblasts. The sporoblasts do not arise by 
a schizogonic division of the pansporoblasts as is commonly ob.served 
among microsporidia; it seems that they are formed by unequal 
(Diagram X a) or binary (Diagrams IX c, X b) fission, each sporoblast 
receiving one pair of nuclei. 
Diagram XII. 
Diagram XIII. 
Diagram XII. (Magnification of Diagram I.) Large cysts with sporoblasts and four 
pansporoblasts. 
Diagram XIII. (Magnification of Diagram I.) Small cysts with sporoblasts, pansporo¬ 
blasts, and spores (only the outlines of the spores are indicated). 
The nuclear division producing the pairs of nuclei is a simple 
fragmentation (Diagram IX a). The nuclei of the pansporoblasts do 
not show any distinct internal structure, the periphery is more 
chromatic than the centre. The dividing nucleus becomes elongated ; 
the two poles are covered by the chromatic substance; in the middle 
no chromatine is left. Finally, the nucleus is divided by an equatorial 
fissure. 
Considering that elements of the host’s tissue were to be found 
among the trophozoites, it is not surprising that nuclei and fibres of 
