H. B. Fantham 
377 
Intra-epithelial schizogony occurs in the Selenidiidae, and the 
intracellular stages are of long duration. The young schizonts in 
S. caulleryi resemble young trophozoites at first in being bluntly 
vermiform (Fig. 3, III), but they become more oval as growth proceeds. 
When they attain a length of about 50/x, nuclear fragmentation occurs 
(Fig. 3, iv), and the schizonts show 200 to 300 small, rounded nuclei 
scattered evenly through the cytoplasm, which does not seem to change. 
The cytoplasm next collects around each nuclear mass, and soon groups 
of small, curved, uninucleate merozoites are produced (Fig. 3, v). Each 
merozoite (in S. caulleryi ) is 10/i to 12/a long and is motile. 
The sporogony of S. caulleryi is not known. That of S. echinatum 
(from Bodecaceria concharum ), as described by Caullery and Mesnil, 
(1899) may therefore be considered. In this case the two free 
Fig. 3. Diagram of the life-cycle of Selenidium , based on that of S. caulleryi (Brasil) and 
S. echinatum (Caullery and Mesnil). Original diagram (H. B. F.). Ill—V, schizo¬ 
gony. VI—IX, gametogony. X—XII, sporogony. 
