ely huge megagamete formed, which
offers a comparatively easy goal for one of the many microgametes.
Nevertheless in the effort to render fertilization absolutely certain, a
few Coccidia have acquired (secondarily) the power of associating; a
state of things which enables those forms, moreover, to effect an
economy in the number of male gametes, only three or four being
developed. Instances are seen in _Adelea mesnili_ (Perez, 1903), _A.
ovata_ (fig. 6), and _Klossia helicina_ (Siedlecki, 1899). It is very
interesting to note that, in the two last cases, unless this association
of the microgametocyte with the megagametocyte occurs, neither can the
former produce male elements (microgametes) nor can the female
individual maturate and become ready for fertilization. (Concerning this
question of association see also GREGARINES.)

In sporogony, great variation is seen with respect to the number of
spores and sporozoites formed; and, as in Gregarines, these characters
are largely used for purposes of classification, under which heading
they are better considered. Usually, the spores (fig. 7) are quite
simple in outline, and not produced into spines or processes;
exceptions are found, however, in a few instances (e.g. _Minchinia
chitonis_). In one case (_Coccidium mitrarium_), the oocyst itself,
instead of being spherical, is curiously shaped like a mitre.

The life-history as a whole is invariably undergone in a single host,
i.e. there is no alternation of true hosts.[6] Schaudinn, in his work on
the _Coccidia_ of _Lithobius_ (1900), showed that the oocysts expelled
with the faeces may be eaten by wood-lice (Oniscus), but when this
happens they pass through the intestine of the wood-louse unaltered, the
latter not being an intermediate host but merely a carrier.

Classification.

The order Coccidiidea is divided into four families, characterized by
the number of sporocysts (if any) found in the oocyst.

Fam. ASPOROCYSTIDAE, Leger. No sporozoites are formed in the oocyst,
the sporozoites being unenclosed (gymnospores).

Genus, _Legerella_, Mesnil. This genus actually conforms to Aime
Schneider's original definition of _Eimeria_, which was founded on
what were really the schizogonous generations of other forms, then
thought to be distinct. In view of the great confusion attending the
use of this name, however, Mesnil (1900) has suggested the new one
here adopted. Two species known, _L. nova_ and _