s. As already said, there can be
little doubt that this was the condition in the Coccidian ancestor,
and it is by no means impossible that one or two forms existing at the
present day remain primitive in that respect. On the other hand, the
advanced character of the parasitism (the parasites remaining
intracellular up to and including gamete-formation); the entire lack
of the characteristic feature of association; the schizogony, which is
only a very rare occurrence in Gregarines, and which, in the present
case, strongly suggests the process in _Caryotropha_ and _Klossiella_;
and, last but not least, the varying number of the sporozoites (3 in
one form, 10-15 in others), which is very different from the almost
constant number (8) in Gregarines, are all characters in which these
forms agree with Coccidia and not with Gregarines. Having regard to
these points, the writer is inclined, for the present, to consider
_Aggregata_ as an offshoot rather from the Coccidian than from the
Gregarine branch of the Ectosporan tree.

BIBLIOGRAPHY.--The following are some of the important papers dealing
with the order:--G. Bonnet-Eymard, "Sur l'Evolution de l'_Eimeria
nova_, Schneider," _C.R. Soc. Biol._ 52, p. 659, 1900; L. Brasil, "Sur
une Coccidie nouvelle, &c.," _C.R.Ac. Sci._ 139, p. 645, 1904; L.
Cuenot, "_Legerella testiculi_ n. sp., &c.," _Arch. Zool. exp._ (N. et
R.), (3) 10, p. 49, 6 figs., 1902; M. Jacquemet, "Sur la systematique
des Coccidies des Cephalopodes," _Arch. Protistenk._ 2 p., 190, 1903;
A. Labbe, "Recherches zoologiques, cytologiques et biologiques sur les
Coccidies," _Arch. zool. exp._ (3), 4, p. 517, 3 pls., 1897; A.
Laveran, "Sur les modes de reproduction d'_Isospora lacazei_," _C.R.
Soc. Biol_. 50, p. 1139, 1898; A. Laveran and F. Mesnil, "Sur deux
Coccidies intestinales de la _Rana esculenta_," op. cit. 54, p. 857, 9
figs., 1902; A. Laveran and F. Mesnil, "Sur la Coccidie trouvee dans
le rein de la _Rana esculenta_, &c.," _C.R.Ac. Sci._ 135, p. 82, 10
figs., 1902; A. Laveran and F. Mesnil, "Sur quelques Protozoaires
parasites d'une tortue, &c." _t. c._ p. 609, 14 figs., 1902; L. Leger,
"Sur une nouvelle Coccidie a microgametes cilies," op. cit., 127, p.
418, 1898; L. Leger, "Sur la morphologie et le developpement des
microgametes des Coccidies," _Arch. zool. exp._ (N. et R.) (3), 6,
1898; L. Leger, "Essai sur la classification des Coccidies,