TT. B. Fantham 
397 
To summarise: it should be noted that the Aggregatidae form 
a perfectly distinct family, somewhat apart from other members of the 
Schizogregarinae. They differ (i) in the absence of association between 
their gametocytes, which entails subsequent fertilisation between aniso- 
gamous free gametes, and (ii) in a change of host being necessary 
to complete their life-cycle. 
Leger and Duboscq (1908, p. 98) point out that in some Decapod 
Crustacea there occur both intestinal and coelomic Gregarines, e.g. in 
Pinnotheres pisum and Eupcigurus prideauxi. In others there occur 
only intestinal Gregarines, as in Chthamalus, Phronima, Gammarus, 
Athanas, while in Inachus dorsettensis, G. Smith (1905) saw only 
coelomic Gregarines. These Gregarines, found in two entirely different 
situations, are quite distinct, a fact which was overlooked before the 
researches of G. Smith in 1905 and Ldger and Duboscq (1907). For 
the intestinal Gregarines of Decapods, Leger and Duboscq (1907) 
proposed the generic name Frenzelina. The members of the genus 
Frenzelina are typical Eugregarines belonging to the family Glepsy- 
drinidae, and are entirely intestinal in habitat. The coelomic cysts 
found in the above-mentioned Decapods belong to Aggregata. 
VII. Systematic. 
In this section it will be convenient to define, as far as possible, 
the diagnostic characters of the various families of the Schizogregarines, 
and then to tabulate the genera and species contained therein, so far as 
known. 
1. Family Ophryocystidae, Leger and Duboscq. 
Schizonts extracellular, increasing simultaneously in volume and in 
number of nuclei. 
Two genera: Ophryocystis and Eleutlieroschizon. 
(1) Genus Ophryocystis, A. Schneider. 
Monocystid Schizogregarines with extracellular schizonts, conical in 
shape, fixed to the epithelium of the host by root-like cytoplasmic 
processes. Gametes isogamous. A single sporocyst, containing eight 
sporozoites, formed after conjugation. 
Nine species are known fi'om the Malpighian tubules of Coleoptera 
(especially Tenebrionidae). 
