200 A. E. Lechmere. 
The following points of resemblance exist between Species II. 
and S. dioica : — 
1. Occurrence of oocysts singly and in rows. 
2. Wall of oocyst sometimes not spotted. 
3. Diameter of oospore. 
4. Undetermined resting period. 
The resemblance between Species II. and 5. Thureti is very 
close, the following points are common to the two species : — 
1. Stout hyphae=40/x. 
2. Shape of oocysts (ordinary). 
3. Occurrence of cylindrical oocyst. 
4. Occurrence of special small oocysts with one oospore. 
5. Number and diameter of oospores. 
6. Resting period more than forty days. 
7. Entire absence of antherocysts. 
In any case, the resemblance between S. dioica and S. Thureti 
is known to be very close, as will be seen from the note following 
the description of the former species. Many earlier workers had 
described species under this name which were later found only to 
be a form of 5. Thureti. The character on which S. dioica is 
absolutely determined is that of the unfailing presence of the 
diklinous antheridial filament. From the fact that Species II. never 
showed the least trace of an antheridial filament, the possibility of 
classing it as 5. dioica must be rejected. 
The reasons have already been discussed for its not being 
classed as S. torulosa. There now remains only N. Thureti, to which 
the resemblance is so very close there seems little doubt that it may 
be classed as this species. 
The only points of difference between Species II. and S. Thureti 
are:— 
1. The absence of spots on the oocyst wall. 
2. The occasional formation of oocysts in rows. 
3. The undetermined resting period. 
4. Various modifications of the method of forming new 
sporocysts. 
Of these differences, the only point which is of any real value 
in determining the species is the absence of spots on the oocyst 
wall. This point in itself may easily be variable within the limits of 
this species; as in the closely related species S. dioica, the membrane 
is found to be either spotted or quite plain. 
