THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 171 



However much (or little) this may prove as to tlie stability of body- 

 form iu the Gregarines, I can not see that it proves anytliiug as regards 

 the Myxosporidia. Further, I can not see any resemblance between the 

 spores of Hthocystis, which contains falciform germs and no capsules, 

 and the capsniate myxosporidian spores. 



Perrier includes it among the Myxosporidia. 



Finally, the following excellent pai)er (seen and incorporated at the 

 last moment) seems to settle the question beyond doubt, and serves to 

 remove almost the last " transition" form from the taxonomic doubtful 

 list: 



L. Cu6uot: Commensaux et parasites des fichinodermes ; Rev. Biolog. Nord 

 France, Lille, v, Oct. 1,1892; Lithoci/stis sekneideri Giard, pp. 4-6, plate 

 1, figs. 1,2. 



The following is an abstract: 



L. schneideri is a perfectly typical monocystid Gregavine; tbe grcgarino stage 

 probably occurs in tbe digestive tube, being rarely encountered iu tbe body cavity, 

 the Gregarine probably encysting soon after traversing tbe intestinal walls. In fact, 

 cysts are encountered ujion, but not attached to, tbe intestinal wall. In tbe body 

 cavity tbe Gregarine was always found (wbetber accidentally or otherwise) in the 

 midst of a mass of cysts. Gregarine ovoid, about 65 ju long, protoplasm very vacuo- 

 late, inclosing a rather large number of clinorhombic crystals, which also occur in 

 the cysts; a voluminous nucleus, with large nucleoli, is present. 



Masses of the spherical cysts, well described by Giard, occur of all dimensions (ad 

 max. 1 to 2 mm.) in different regious of the body, especially on the intestine and on 

 the oral surface. They inclose a considerable number of spores and a voluminous 

 rest of segmentation riddled with the same crystals that occur in the Gregarine. 



Spores of variable dimensions (megaspores 24 /<, microspores 12/<), ovoid, distal 

 end neatly truncate, proximal end rounded; spores limited by a unique refringent 

 integument (endospofe) situated at the extremities of small, very delicately walled 

 tubes, which latter form a sort of more or less U7idulatiug epispore. 



Spores arranged, at least in the large cysts, in a number of small, radial groups, 

 formed by the convergence of the tubes to a common center. Contents of young 

 spores granular; of mature spores 8 falciform corpuscles (4 at each eud), and a central 

 rest of segmentation. The falciform corpuscles are probably expelled on the death 

 of the host, and other Echinocardiums naturally become infected by swallowing the 

 sand containing them. 



Pigmcut identical with the products of dissimilation spread through the tissues 

 of the host; if specially condensed around the cysts, it is as a result of the [increased 

 tissue] expenditure necessitated by their considerable growth. 



The presence of small nodosities on the test could not be determined. 



The cysts, united into more or less voluminous masses, are surrounded by a con- 

 siderable mass of black pigment and of amoeboid cells, the latter very evidently 

 Echinocardium amcebocytes accumulated around the foreign bodies. The latent life 

 of the cysts is probably not very long, as there are frequently seen, apparently in 

 process of degeneration, small ones inclosing only empty spores absolutely devoid 

 of nuclei. 



As iu all the other Monocystids studied, the Lithocystis spore has dissimilar poles, 

 the one truncate, the other rounded and furnished with a long tube. The structure 

 of the cysts is appreciably diifereut from all other known Monocystids. 



