170 REPORT OF THE COMMISSIONER OP FISH AND FISHERIES. 



ffahitat. — r>ody cavity of Echinocardinm cordatum (sea-urchin), par- 

 ticularly against tlie test between the mouth and subanal plastron, and 

 esi)ecially toward the conical point which terminates the ])lasti(ui 

 interiorly; also frequently on the inner side of the actinal curvature 

 of the intestine. 



Nature. — Giard says: 



I Lave found nothing resomblinj; tlio Orcsrarines, and the whole of the facts 

 observed lead ine to approximate the para.site not to the lower animals, but to the 

 lower plants (Myxomycetes and Chytridlnea'); on the other. hand, the spores being 

 identical with those described as arising in the cysts of the Gregaiines, one may ask 

 whether the relation of the Psorospennice to the Gregarines is not a relation of para- 

 sitism rather than of genetic bonds. 



Prof. Biitschli, the only other 'author who has (as far as I know) 

 commented upon this form, says:^ 



It may indeed be possible that an organism as yet unfortunately only briefly de- 

 scribed by Giiird, his f»o-called Lilhocystis Hchticideri, occupies a sort of middle ground 

 between Gregarines and Miixosporidia, since it combines the plasmodioid nature with 

 the production of spores similar to the Myxonporldia, together with the develo))nieut 

 of sickle-shaped germs in these spores. Unfortunately, however, as said, Lithoi-ystis 

 has not yet been fully described, so that the decision is at present somewhat difticult. 



Prof. Lankester ^ places LitJiocystis among the genera of the Alyxo- 

 sporidia. Pfeilfer^ says that this species forms "a transition to a still 

 unknown side." 



Remarks. — First as to Giard's opinion, which is entitled to especial 

 weight as being derived directly from a study of the form itself, while 

 Biitschli's is here to a certain extent an opinion of an opinion. In 

 Giard's article I fail to find the slightest indication of a desire to api)roxi- 

 mate Lithocystis to the Myxosporidia. True he calls it a "psorosperm," 

 but he uses this term in a very vague sense, its scope ai)peariiig to be at 

 least equivalent to that of the term Sporozoa. Further he states that: 



The whole of the facts observed lead me to approximate the parasite not to the 

 lower animals but to the lower plants (Myxomycetes and Chytridinew). 



Then he argues that since the spores of Lithocystis are identical with 

 the spore-like contents of the gregarine cysts, perhaps the latter 

 (which he also denominates " psorosperms ") are not gregarine spores, 

 but gregarine parasites. 



Prof. Biitschli, however, says that Avhile its spores agree with those 

 of the Gregarines in containing falciform germs, Lithoeystis possesses 

 in common with the Myxosporidia^ a plasmodioid nature and the pro- 

 duction of similar spores. 



• Es ware sogar miiglich, dass ein bis jetzt leider iiur fliichtig von Giard bcschrieb- 

 nerOrganismus, seine sogenaunte LithocystiH schneideri, cine Art Mittelstufe zwischeu 

 Gregariniden nnd Myxosporidien einuimmt, da er das plasuiodieuartige Wesen mit 

 Erzeuguug iihnlichor Sporeu wie die Myxosporidien, sowie der Hervorbildung 

 sichelformiger Keime in diesen Sporeu vereinigt. Leider istjedoch, wie ges.agt, die 

 Lithocyslis noch nicht eingehend beschriebeu so dass ihre Beurthcilung bis jetzt 

 etwas schwer fiillt (Hronu's Thier-Reich, 1882, i, p. 602). 



^Encycl. Britau., 1885, 9 ed., xix, p. 855. 



'Die Protozoen als Krankheitserreger, 1890, 1 ed., p. 49. 



