THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 177 
Tubes rather frequent in very many fresh-water copepods, the affected 
[Page 15] individuals being distinguishaBle at first glance from the healthy by their 
opacity, the places where the parasites lie appearing dark. If in great 
number, the Cyclops appear completely opaque, and, indeed, according to 
[Page 16] Schmeil (loe. cit., p. 20), may appear dark brown to black. Discoloration 
caused by larger or smaller tubes filled with pyriform, spore-like cor- 
puseles; tubes occurring in body-cavity, and various other places, as the thorax, 
abdomen, tail, natatory feet, and first antenne ; sometimes in so great numbers that 
no part of the body is free from them. Spores in some places not in tubes but free 
in body-cavity, then always found directly on the muscles. 
These parasites were probably those which Claus observed in copepods and 
regarded as spores of fungi; also extremely probably those noted by other obseryv- 
ers, in various crustacea, e. g., Henneguy in Palemon rectirostris and P. serratus, 
Henr.eyuy and Thélohan in Crangon vulgaris and Astacus fluviatilis, and Garbini in 
Palemonetes varians. However, it cannot with certainty be asserted that the 
parasites found in the last-mentioned crustaceans are identical with the Cyclops 
parasite, as to the short communications no figures! are added, and the authors in 
question were unable to follow the whole developmental history. 
Technique.—The affected Cyclops was isolated in a drop of water on the 
[Page 17] slide and covered with a cover glass provided with wax feet, fixed in posi- 
tion by careful pressure on the angles of the cover-glass, so that it 
remains quiet and can be conveniently observed even with a high power (apochr. 
4mm.). Between the observations the Cyclops was at first kept in a hanging drop 
in the moist chamber, but lived only a few (2-3) days, dying partly from starvation, 
partly from other unfavorable conditions. Consequently the Cyclops was next 
kept in a watch-glass of water, thus securing necessary food supply. Thus kept, 
it lived 14 days, allowing the development of the parasites to be followed. 
Several individuals were kept simultaneously and examined 2 to 4 times a day. 
Investigation of dead or crushed specimens is not to be recommended, as great bacte- 
rial development soon disturbs the study. For observation of the finer anatomical 
features and the developmental stages, the parasites were isolated by crushing the 
host and observed with very high powers (homog. immers. apochr. 2 mm., oc. 12 
and 18). For fixation, picro-sulphuric, and chromo-aceto-osmic acids; for stains, alum 
carmine, hematoxylin; also methyl violet, safranin, and fuchsin. Examinations 
were made partly in water, partly in glycerin. 
1. Amebiform stage.-—Met with in all parts of the body; most easily 
[Page 18] observed on the first antennae. Form ameboid-variable, globular or 
elongate; dimensions varying from 7u long by 34 broad, to 20u long by 
6u broad. Plasma finely granular, capable of emitting on all sides blunt, lobulate, 
hyaline pseudopodia, always possessing a nucleus (pl. 4, fig. 2. N) and a small con- 
tractile vacuole (c. ve). Nucleus globular, showing the familiar vesicular structure, 
- that is, in its interior, a globular, homogeneous, more strongly refringent and more 
deeply staining nucleolus [Binnenkorper]. Contractile vacuole constantly situated 
near the border, in the end of the body which during progression is hindermost, pul- 
sating about once every 30 seconds; no food vacuole perceptible. 
This ameeba ordinarily creeps about over the epithelial and muscle cells and prob- 
ably feeds upon the same, as, although not directly observed, many epithelial cells 
were seen destroyed, and wpon them amb. 
After attaining a certain size the amcebx gradually cease their movements, draw 
in their pseudopodia, and encyst themselves. 
The ameebie may fuse to large plasmodes; several such fusions of 2 or 3 amb 
(pl. 4, fig. 8) were directly observed. Size of plasmodes varying with ‘size and 
1The author is partly in error as regards the absence of figures. They will be 
found in the papers of Henneguy and Garbini, 
FC 12 
