THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. Fit 
However much (or little) this may prove as to the stability of body- 
form in the Gregarines, I can not see that it proves anything as regards 
the Myxosporidia. Further, I can not see any_resemblance between the 
spores of Lithocystis, which contains falciform germs and no capsules, 
and the capsulate myxosporidian spores. 
Perrier includes it among the Myxosporidia. 
Finally, the following excellent paper (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. Cuénot: Commensaux et parasites des Echinodermes; Rev. Biolog. Nord 
France, Lille, v, Oct. 1,1892; Lithocystis schneidert Giard, pp. 4-6, plate 
1, figs. 1, 2. 
The following is an abstract: 
L. schneideri is a perfectly typical monocystid Gregarine; the gregarine stage 
probably occurs in the digestive tube, being rarely encountered in the body cavity, 
the Gregarine probably encysting soon after traversing the intestinal walls. In fact, 
cysts are encountered upon, but not attached to, the intestinal wall. In the body 
cavity the Gregarine was always found (whether accidentally or otherwise) in the 
midst of a mass of cysts. Gregarine ovoid, about 65 uw 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. 1to 2mm.) in different regions 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 44, microspores 12 jz), ovoid, distal 
end neatly truncate, proximal end rounded; spores limited by a unique refringent 
integument (endospore) situated at the extremities of small, very delicately walled 
tubes, which latter form a sort of more or less undulating epispore. 
Spores arranged, at least in the large cysts, in a number of small, radial groups, 
formed by the convergence of the tubes toa common center. Contents of young 
spores granular; of mature spores 8 falciform corpuscles (4 at each end), and acentral 
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. 
Pigment 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 amcboid 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 in all the other Monocystids studied, the Lithocystis spore has dissimilar poles, 
the one truncate, the other rounded and furnished with along tube. The structure 
of the cysts is appreciably different from all other kvwown Monocystids. 
