PROTOZOA 



429 



COCCIDIUM OVIFORME LEUCKART. 



Synonyms. Coccidium cuniculi Rivolta (Anat. physiol. 

 1878). 



Morphology and development. In the encysted state, as 

 it may be found in the biliary canals of infested rabbits, the 

 parasite is an ovoid body 30 /x to 50 /x long by 14 /x to 28 

 P broad enclosed in a double contoured shell (cyst), with a 

 depression (micropyle) at one of its poles. At first the cyst 

 is filled with protoplasm ; very soon the latter separates from 

 the wall and contracts into a nucleated spherical mass. It is 

 the last phase of parasitic development observed in the liver; 

 the coccidia pass with the bile from the liver into the intestine, 



Pig. 98. Coccidium ovit'orme from a rabbit's liver, a and b, young 

 stages in the epithelial cells of the bile duct; c, d and e, oocysts; 

 f, g and h, spore formation; i, spore with sporozoite. (After 

 Doflein). 



and are carried out with the excreta. Their ulterior evolution 

 takes place in water or in moist earth. If some of the ripe 

 cysts from an infested liver are placed under a thin layer of 

 water, on damp sand, or on a piece of charcoal in a moist 

 chamber, their development may be followed. The rapidity of 

 their evolution depends upon the conditions of temperature 

 and oxygenation in which they are placed. The process may 

 be completed in from ten to fifteen days (Balbiani), or in four 

 or five days according to R. Pfeiffer. Segmentation divides 

 the protoplasmic sphere into two, then into four smaller spheres 

 or sporoblasts ; each of these elongates, surrounds itself with a 

 double membrane, and becomes a sporocyst. The division of 

 the contents of each sporocyst results in the formation of two 

 nucleated comma-shaped protoplasmic bodies (sporozoites) 



