4 PORTER. [Vor. XIV. 
The process of spore formation seems to be somewhat differ- 
ent in the later stages of sporulation; for, as the protoplasm 
becomes riper, sporogonia can be seen developing not only at 
its periphery but also within it (Pl. I, Fig. 13, sfo’go’). During 
this process the particles of chromatin appear at first to collect 
together in large masses (Pl. I, Fig. 13, chr) and then to be 
distributed to the forming sporogonia. At length the proto- 
plasm that still remains breaks up into small masses (PI. I, 
Fig. 15, 7/2) and finally becomes employed in the formation 
of additional sporogonia. One frequently finds, however, in 
mature cysts — that is, those containing only ripe sporocysts— 
a small mass of loose protoplasm left over when the formation 
of the sporogonia has ceased. 
The sporogonia that are formed first do not wait in their 
development for those that are formed later, but continue their 
growth and metamorphosis without interruption, so that one 
finds in the same cyst sporogonia in all stages, from such as are 
just formed to those that are mature (PI. I, Fig. 15, spo’go and 
spo’'go', and Pl. II, Fig. 16). 
In one case, I have noticed within the cyst at about this 
stage delicate transparent membranes (Pl. I, Fig. 15, 0). 
What their purpose is I cannot say, unless possibly they are 
connected with the formation of the sporocysts. 
The development of the sporogonia into sporocysts each con- 
taining eight spores, is as follows: The nucleus first, apparently 
without mitotic changes, divides into two (PI. II, Fig. 20), then 
each of these divides, making four (PI. II, Fig. 21), and finally 
each of the four divides, thus producing in all eight nuclei (PI. I, 
Figs. 15, sfo’go, and Pl. II, Fig. 17). The example shown in 
Pl. II, Fig. 19, seems to be an exception to this rule, for here 
there is a well-developed nucleus at one pole, and near the 
other a collection of chromatic particles not very compactly 
arranged and without nuclear membrane or precise boundary. 
The only explanation I can offer is that abnormally the division 
has resulted in nuclei of very unequal size. 
After their formation the sporogonia increase greatly in size. 
Pl. II, Fig. 17, shows five sporogonia, four before any division 
of the nuclear substance, and one after the three successive 
