284 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 
The description is based upon the (in the main) accordant results of 
Lieberkiihn, Balbiani, Biitschli, and Pfeiffer, particularly upon those 
of the last two observers. Gabriel’s accordant results have been incor- 
porated, his divergent ones mostly footnoted. 
Life-history (Pteiffer).—Emerging from the spore, the young myxo- 
sporidium (until now the sporoplasm) next penetrates into the interior 
of the red blood corpuscles or of the cells of the bladder epithelium. 
Its intracellular existence continues until its increasing size ruptures 
the cell wall, when it escapes, differentiates its own protective ecto- 
plasmic layer, and resumes amceboid movements. Finally endogenous 
(pansporoblastic) spore formation takes place, the spores ultimately 
become free, and the life-cycle is complete. 
Cyst none. 
Myxosporidium..—Form varying much with age; at exit from spore 
globular-amceboid: while within, and at the time of exit from the 
epithelial and red blood cells, roundish; older forms cylindrical, ribbon 
or club shaped, or irregularly amoeboid, presenting a very grotesque 
appearance, with branches, forkings, and long appendages. Size vary- 
ing with age up to a maximum length of 300 « (Biitschli) by a breadth 
of 136 4. Youngest myxosporidia colorless; older ones colored yellow- 
ish or reddish or brownish-red by inclusions of extraneous pigment in 
the endoplasm. Myxoplasm, in all but the youngest stages, presenting 
a clear differentiation of ectoplasm and endoplasm. 
Ectoplasm forming a rather thick, very transparent, colorless, deli- 
cate, finely granular layer, containing none of the characteristic endo- 
plasmic elements; end in contact with the mucous membrane, colorless, 
destitute of granules, leafy or pronged for attachment. Opposite end 
richest in granules and in pigment, free-floating, usually rounded; free- 
floating forms partly agreeing with the above, differing, however, in 
being destitute of pronged processes, showing at times some peculiar 
differentiations, particularly the appearance shown on pl. 44, fig. 3, 
where it seems permeated by a system of canals. One end of body 
often more or less plainly radiate-striate, the usual distinction between 
the ectoplasm and endoplasm being here absent. This Prof. Biitschli 
regards as the attached (pronged) end. Also not rarely are seen a series 
1Gabriel believed that the bladder does not furnish a suitable environment for 
metasporal development, consequently the latter must, he thinks, take place in or 
via the external world. In his opinion the myxosporidia living within the bladder 
represents not normally developing, but progressively degenerating forms. Such 
development as occurs within the bladder, by which apparently the way has been 
prepared for the replacement, at least within certain limits, of the perishing mother 
organisms, does not exclude the possibility of ripe spore-containers or free spores 
finding their way to the outer world and there under favorable (but as yet unknown) 
conditions developing. ‘This supposition, a necessary postulate, becomes a certainty 
when it is remembered that only thus [by active or passive migration] could the 
parasite have reached the bladder. Probably repeated, though perhaps (as indicated 
by the variations in their occurrence) not continuous, infection-immigrations occur. 
