COCCIDIA 71 



numerous " sporocysts," which have a disclike appearance. Each 

 contains two sporozoites and a comparatively large residual body. 

 Eimeria lacazei is, like A.evata, of comparatively common occurrence; 

 it is distinguished by the oval form of its schizonts. E. schubergi, the 

 schizonts of which are ball-shaped, is of rarer occurrence. Both the 

 Eimeria, however, vacate their host soon after fertilization ; the oocysts 

 when formed pass out in the faeces and sporogony takes place in the 

 open. This process may be followed by keeping the live centipedes in 

 flat glass dishes, the bottoms of which are covered with blotting paper 

 over which cover-glasses are laid. To keep the cover-glasses in place, 

 well damp the blotting paper, otherwise they may be deranged by the 

 movements of the centipedes. The droppings of infected animals are 

 generally somewhat soft and may be readily spread out on the cover- 

 glasses and examined. 



Permanent coloured specimens are made by fixing cover-glass 

 preparations of the intestinal contents in alcoholic solution of mer- 

 curic chloride, staining with diluted haematoxylin, and differentiating 

 with eosin. The most important point for observation is the structure 

 of the nucleus. To study the effects of the parasites upon the intes- 

 tinal epithelium, fix the entire gut unopened in alcoholic solution of 

 mercuric chloride and cut in series. 



It is important to remember that, in addition to the Coccides, two 

 large polycystic species of Gregarine are found, though not very fre- 

 quently, in the gut of the centipede. 



(b) Coccidia found in the Kidney of Helix. 



Another variety of Coccides which is very readily obtainable is 

 parasitic in the kidney of certain land snails. It is found in the 

 common garden snails, Helix nemoralis, L., and H. hortensis, Muell. 

 Its frequency varies with locality, but it is generally present in one 

 out of several examples. 



The shell should be removed from the snail in small pieces with a 

 strong pair of tweezers, one point of which is inserted between the 

 mantle and the shell. The kidney lies lengthwise in the largest and 

 lowest spiral of the visceral sac, and is easily seen on account of its 

 superficial position and yellow colour. A piece should be cut off with 

 the scissors and teazed out in normal saline or, better still, in a drop 

 of blood from the snail. The resulting liquid will be found to have 

 a milky cloudiness, due to the large quantity of opaque urinary con- 

 cretions. These concretions are knobbly and irregular in shape, and 

 are frequently enclosed in isolated, but otherwise undamaged, kidney 

 cells. The parasites, which belong to the species Elossia helicina, are 

 also frequently found in the host-cells, which become much enlarged. 



