THE MYXOSPORipiA, OR PSOROSPERMS OF FISHES. 2G3 



amceboid spoioplasm from the spore (see below) causes liim to support 

 the opinions of" Lieberkillin and Balbiani. Unfortunately, however, 

 he adds the following': 



Filially, also, tlie observiitious of Thelolian upon tho failure of the lilauients iu 

 the capsules of many spores is not favoraV.le to the mode of view of Miugazziui. 



Here again we have the ribbonettes and the capsular filaments con- 

 founded, another instructive Avarniug 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 Myxosporxdia, long- 

 drawn-out, tailed bodies, which move in Gregarine fashion, but which, on the other 

 hand, are connected by manifold transitions with the amoeboid forms. 



Spore formation.— K'^\mV\iY of spore formation is truly extraordinary, 

 most of the individuals having spores formed or in course of formation 

 in less 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 tlie yellow protoplasm. Tliis vacuole presently acquires an envel- 

 oping membrane, and within it is formed the spore. Its theca sliows 

 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 forjn at the periphery, they form, in growing, a sort of crown 

 around the individual, and the sp(n-e is not set free until the enveloping 

 membrane is well formed (Mingazziui). 



Normally the pansporoblast shows at some portion of its circum- 

 ference a distinctly semilunar aggregation of protoplasmic granules. 

 Under the iafiuence ot reagents (e. g., osmio and sulphuric acids) the 

 pansjioroblast membrane bursts, discharging its contents, and remaining 

 as a. hyaline empty sac (Perugia). 



^^^ore.— Untailed: cuncate-ovate; capsules 4. Perugia saw the exit 

 of the sporoplasm from a spore of the gall bladder of T. narl<e. The 

 large strite on the slndl render the posterior border of the shell in con- 

 tour dentate (Thelohan, 1802 j see also p. 2(51). 



