Syn.: _Monocystis stiedæ_, Lindemann, 1865; _Psorospermium cuniculi_, Rivolta, 1878; _Cytospermium hominis_, Rivolta, 1878; _Coccidium oviforme_, Leuckart, 1879; _Coccidium perforans_, Leuckart, 1879; _Coccidium cuniculi_. [Illustration: FIG. 70.--_Eimeria stiedæ_. Section through an infected villus of rabbit’s intestine. × 260.] _Eimeria stiedæ_ is parasitic in the gut epithelium (fig. 70), liver, and epithelium of the bile ducts of rabbits, and is usually considered to be the parasite very occasionally found in man. The life-cycle resembles that of _Eimeria avium_ in its general outlines (see fig. 69) and therefore will not be detailed in full here. The oöcysts (fig. 71) are large, elongate-oval, greenish in fresh preparations and vary in size from 24 µ to 49 µ long and 12·8 µ to 28 µ broad, the gut forms being usually smaller than those occurring in the liver, owing to the more confined space in which they are formed. Formerly, the parasites in the liver were described under the name of _Coccidium oviforme_, while those from the intestine were termed _Coccidium perforans_. This distinction has now broken down. [Illustration: FIG. 71.--_Eimeria stiedæ_, from the liver of the rabbit, oöcysts in various stages of development. (After Leuckart.)] [Illustration: FIG. 72.--_a_, _b_, spores of _Eimeria stiedæ_ (Riv.), with two sporozoites and residual bodies; _c_ represents a free sporozoite. (After Balbiani.)] [Illustration: FIG. 73.--So-called swarm cysts (endogenous sporulation or schizogony) of the Coccidium of the rabbit. The daughter forms are called merozoites. (After R. Pfeiffer.)] The oöcysts[176] are thick-walled, somewhat flattened at one pole, where a large micropyle is present. Four egg-shaped spores (sporocysts) are formed within, each about 12 µ to 15 µ long and 7 µ broad (fig. 72). The oöcysts are voided with the fæces. Sporogony takes, in nature, about three days in the excrement. Fæcal contamination of the food of rabbits results, and coccidian oöcysts are swallowed. Under the influence of the pancreatic juice of a new host, the sporozoites (fig. 72, _a_--_c_) are liberated from the spores and proceed to attack the epithelium and multiply within it, as in the case of _Eimeria avium_. From the gut, infection spreads to the liver, where multiplication of the parasite goes on actively, resulting in the formation of the whitish coccidial nodules, which may be very conspicuous (fig. 74). Proliferation of the connective tissue may occur around the coccidial nodules, which then contain large numbers of oöcysts in various stages of development. It is said that the oöcysts in the older nodules do not seem to be capable of further development. Schizogony (fig. 73) and gametogony in all stages can be found in both liver and gut.