372 
Th e Sch izogregarines 
are more especially prevalent in the two great phyla, the Arthro- 
poda and the Annelida. They are also known in Mollusca and 
Ascidiacea, 
The genera Ophryocystis and Schizocystis occur among the Insecta. 
Various species of Ophryocystis are found in the Malpighian tubules of 
beetles belonging to the genera Blaps, Aids, and Olocrates, whilst 
Schizocystis, of which only one species, S. gregarinoid.es, is known, is 
found in the gut of the larva of a species of Geratopogon, a dipterous 
Insect occurring in the Alpine Lake Luitel. 
Various species of Selenidium have been recorded from Polychaetes : 
Protula, Spio, Scololepis, Serpula, Dodecaceria, etc. Selenidiidae were 
described from the Gephyrean Pliascolosoma in 1907, and last spring 
(1908), while working at Banyuls, I observed two forms of Selenidiid 
parasites in the gut of the Terebellid, Polycirrus aurantiacus. Of 
the species of Selenidium from the above-mentioned Polychaetes many 
require re-investigation, for some of them were described many years 
ago by Ray Lankester (1863), Giard (1884) and others, the description 
often applying only to what is now known as the trophozoite phase, for 
Selenidium is characterised by the presence of well-marked longitudinal 
myonemes. 
Merogregarina amaroucii Porter (1908) in the alimentary tract of 
the composite Ascidian, Amaroucium sp. (from Port Jackson, New 
South Wales), is the only example known up to the present of a 
Schizogregarine from a Protochordate. No true Schizogregarine has 
yet been recorded from the Chordates. 
A number of species of Aggregata have been described recently by 
Leger and Duboscq as “coelomic” Gregarines which occur in certain 
crabs of the genera Portunus, Eupcigurus, Inachus, etc. The sporogonic 
phases of the life-histories of these parasites have now been shown by 
Moroff, and Leger and Duboscq to occur in the Cephalopod molluscs, 
Sepia and Octopus. Moroff (1908) has described a number of new species 
from the octopus. 
The stages of the organism formerly known as the gymnosporous 
Gregarine, Aggregata (Frenzel and Labbe), are the schizogonic stages 
of a parasite, whose sporogonic stages wei'e formerly known as Eucoc- 
cidium or Benedenia or Legerina in Cephalopods. As the distribution 
of the Schizogregarines appears to be somewhat scattered, I have, 
for the sake of clearness and brevity, placed the main facts regarding 
them in tabular form (see p. 397 et seq.). 
The effect of Schizogregarines on their hosts is chiefly to cause the 
