290 J. JACKSON CLARKE. 



ofLumbricus agricola prismatic pseudo-navicellse exactly 

 like those described by Bosanquet^ in the body-cavity. 



The observations made by Wolters on Clepsidrina blat- 

 tarum are, unfortunately, scanty. Much remains to be done 

 with regard to the earlier phases, both of the poly- and the 

 raono-cystides. More importance attaches to Wolters's 

 description of certain phases of Klossia helicina. This 

 parasite is of great interest from the position it holds be- 

 tween the Gregarines and the Coccidia. From the fact that 

 conjugation has not been observed, I, like L. PfeifFer,^ should 

 be inclined to place it with the latter group. First described 

 by Kloss^ of Frankfort, it has since been described by A. 

 Schneider and by L. Pfeiffer (loc. cit.). To the latter author 

 I am indebted for many beautiful preparations of the parasite 

 in Helix hortensis and Succiuea Pfeifferi. Pfeiffer has 

 arrived at some interesting conclusions based on the study of 

 this parasite. Of these the more important are — 1st, the 

 phenomenon of multiple '^ infection, as many as fifteen parasites 

 being found within a single epithelial cell ; 2nd, that when 

 multiple infection occurs only one of the parasites reached 

 maturity ; and 3rd, that the size attained by the parasite is 

 determined by the size of the epithelial cells of the kidney of 

 the species of snail infested by the parasite, though in all cases 

 the sporogonia have the same dimensions, the number of 

 sporogonia varying with the size of the parasite from which 

 they are derived. 



The general features of Klossia I have never seen better 

 than in some common grey slugs which I examined in July, 

 1892. The slugs were found in a hollow in the rocks below 

 the falls of the river Shin, in Sutherland. With them were 



' W. C. Bosanquet, 'Quart. Journ. Micr. Sci.,' 1894, No. 143, p. 421, 

 fig. 19. 



^ L. Pfeiffer, 'Protozoen als Kraiikheitserriger,' 1891, p. 72. 



^ Hermann Kloss, ' Senkeubergisclie Abhandlungen,' vol. i, 1855-6. 



■' L. Pfeiffer compares ibis with what occurs in the Sarcosporidia, the micro- 

 sporidia in Coccidium salamandrro, and in the Coccidia of the kidneys of 

 he goose and the dog. 



