THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 263 
amceboid sporoplasm from the spore (see below) causes him to support 
the opinions of Lieberkiihn and Balbiani. Unfortunately, however, 
he adds the following: 
Finally, also, the observations of Thélohan upon the failure of the filaments in 
the capsules of many spores is not favorable to the mode of view of Mingazzini. 
Here again we have the ribbonettes and the capsular filaments con- 
founded, another instructive warning against the application of the same 
name to two entirely different structures (see also p. 87). 
Perugia further remarks (p. 138) that if the “ gregarinoid forms” be 
regarded as larval stages the adult forms represent a retrogression, 
inasmuch as the “ gregarinoids” with a nucleus and the protoplasm 
regularly disposed, need only a cuticle to be monocystids, while the 
adult stages, destitute of a nucleus and with the protoplasm never 
regularly disposed, are much farther removed therefrom. Perugia was, 
however, unable to find any such “ gregarinoid forms.” 
Kruse, however, says: 
Very interesting is an observation of Mingazzini’s, which the author can confirm. 
In the gall bladder of the Selachians are found, besides typical Myxosporidia, long- 
drawn-out, tailed bodies, which move in Gregarine fashion, but which, on the other 
hand, are connected by manifold transitions with the amceboid forms. 
Spore formation.—lRapidity of spore formation is truly extraordinary, 
most of the individuals havin g spores formed or in course of formation 
in Jess than 15 minutes. At undetermined points in the endoplasm (in 
the middle or near the periphery) appear round vacuoles of clear proto- 
plasm, which, like the ectoplasm, originate by a rapid transformation 
of the yellow protoplasm. This vacuole presently acquires an envel- 
oping membrane, and within it is formed the spore. Its theca shows 
an oblique striation in two directions. Spores may arise in individuals 
whose protoplasm is little modified, i. e., almost entirely composed of 
yellow granules, the spores being then inclosed in a membrane, round 
in form, formed from the yellow protoplasm, and containing also a col- 
orless refracting liquid; or the spores may form in colorless protoplasm, 
in this case without the enveloping membrane, the spores issuing free 
and floating in the bile. Where, as sometimes happens in the first case, 
spores form at the periphery, they form, in growing, a sort of crown 
around the individual, and the spore is not set free until the enveloping 
membrane is well formed (Mingazzini). 
Normally the pansporoblast shows at some portion of its cireum- 
' ference a distinctly semilunar aggregation of protoplasmic granules. 
Under the influence of reagents (e. g., osmic and sulphuric acids) the 
pansporoblast membrane bursts, discharging its contents, and remaining 
as a hyaline empty sac (Perugia). 
Spore.—Untailed; cuneate-ovate; capsules 4. Perugia saw the exit 
of the sporeplasm from a spore of the gall bladder of Z. narke. The 
large strive on the shell render the posterior border of the shell in con- 
tour dentate (Thélohan, 1892; see also p. 261). 
