H. B. Fantham 
371 
of Sporozoa. A correct appreciation of the value of the amoeboid 
character of the organism in the two species of Ophryocystis ( 0. 
buetschlii, 0. francisci) then known was first attained by Leger in 1900, 
when he described an allied parasite, which he called Schizocystis 
gregarinoides, from the gut of the larva of the fly, Ceratopogon. Schizo¬ 
cystis has a fixed and definite contour, and Leger showed that the so- 
called pseudopodia of Ophryocystis were merely stiff, root-like processes, 
for fixation of the extracellular parasite to the cells of the gut wall 
(Fig. 4, A, B). 
In 1898 Caullery and Mesnil described a parasite, Gonospora 
longissima, in which an intracellular stage of asexual multiplication or 
schizogony occurred. In 1907 Brasil published his account of Selenidium 
caulleryi from the digestive tract of the Polychaete, Protula tubidaria, 
and definitely placed the genus Selenidium (of the new family 
Selenidiidae) in the Schizogregarinae, pointing out that those forms of 
the parasite which divided asexually were intracellular in habitat, in 
contradistinction to the extracellular character of those of Ophryocystis 
and Schizocystis. 
Leger (1907) at this time published a paper on the genus Ophryo¬ 
cystis. Recently there has appeared the paper by Leger and Duboscq 
(July, 1908) on Aggregata and “ Eucoccidium,” wherein the former 
(.Aggregctta , till recently considered as a gymnosporous Gregarine of 
crabs) is shown to be the schizogonic or asexual multiplicative cycle of a 
Schizogregarine, which passes through its spore-producing cycle in the 
gut-epithelium of cuttlefish (as the so-called “ Eucoccidium ” or Bene- 
denia). Still more recently a detailed study of a new Schizogregarine 
has been completed by my friend and fellow worker, Miss Annie Porter 
(August, 1908) 1 . The parasite described by Miss Porter has been named 
Merogregarina amaroucii, and it occurs in the gut of a composite 
Ascidian from Australia. Other Schizogregarines belonging to the 
Selenidiidae have been described by Brasil and by the present author 
(1907) in various Annelids. 
III. Occurrence of the Various Genera. 
The Schizogregarines almost invariably occur in the lumen of the 
gut of their hosts or in a channel leading therefrom, such as the 
Malpighian tubules in Insects. So far as present knowledge goes they 
1 The paper is now in the course of publication ; a preliminary communication was 
published in Oct. 1908. 
