390 
The Schizogregarines 
needed on schizogony and sporogony. The sporogonic stages should 
be looked for especially at the time of reproduction of the Annelid 
hosts. Sections should be made of the digestive tracts of parasitised 
hosts for stages of schizogony of the parasite. 
(6) Genus Merogregarina. 
A new Schizogregarine from the alimentary tract of a Protochordate, 
namely, the Composite Ascidian, Amaroucium sp. has recently been 
described. The host came from New South Wales. The parasite 
belongs to a new genus, and Miss Annie Porter, who discovered it in 
1908, has given it the name Merogregarina amaroucii (Fig. 8). The 
trophozoites occur in fair abundance in the gut of the host, and in 
some places a very heavy infection occurs in the lumen of the gut. 
The free trophozoites are 23/a to 31/r long and from 11/r to log broad 
(Fig. 8, A, B). They are non-septate or monocystid. An epimerite 
about 4/x to 6g long is present and it is shaped like a lance-head 
(Fig. 8, A, ep). Each trophozoite possesses a well-defined cuticle, a 
clear ectoplasm and a granular endoplasm. Myonemes are seen in the 
Fig. 8. Merogregarina amaroucii Porter (1908). Original drawings by Miss Annie Porter. 
A. Trophozoite with lance-shaped epimerite (ep). Myonemes (mg) in pre-nuclear 
region. Large nucleus with marked karyosome (kg), and plasmosomes. 
B. Trophozoite whose epimerite is lost. Karyosome somewhat dumb-bell shaped. 
C. Section of gut of Amaroucium sp. showing group of merozoites cut longi¬ 
tudinally. The channel by which they issue singly into the lumen of the 
gut is here seen to be open. 
D. Sporoeyst in longitudinal section, showing sporozoites. 
E. Sporoeyst in transverse section, showing eight sporozoites cut across. 
