TrtE MYXOSPORtDiA, OR PSOROSPERMS OP FISHES. 261, 



Structure of the Kpore, viz, '"Jts theca shows an obli(jue striation iu 

 two contrary directions." Moreover, he unfortunately fails to indicate 

 the si)ecies of fishes which he examined.' 



Perugia, however, has given a list of the species of fishes he exam- 

 ined, which includes 2 species investigated by Ley dig. He says: 



While Leydig had observed that curtain spores were stri-ited and others not, 

 Miii;j;azztui says that the striiB are comniou to ;ill, and is of opinion that tliore is 

 qnestion of but a single species, an opinion whicii I believe to be correct. 



In describing GMoromyxum leydufii, Theh>han* says it has 

 Great striie upon the shell, which, in passing ronnd the posterior part of the spore, 

 give it a toothed appearance. 



It is thus evident thatheiucludes witli the present species (\ inchum. 

 As there is riothing, however, anywhere iu the literature to sliow that 

 he himself ever studied the spores of G. inci,snm, it is very probable that 

 this statement is oidy intendedas representing the consensus of opinion, 

 that is, ]\Iingazzini's and Perugia's views. 



As regards ^Mingazzini's, we have (1) no evidence that he ever 

 examined the gall bladder of Raja batis, and (2) only the very loose 

 statement given above (which practically anu>unts to nothing), so that 

 his opinion that there is but one species is a mere dictum, and even that 

 does not necessarily, as far as the record shows, refer distiiu'tly to this 

 case. 



Further, although Perugia notes the discrepancy between Leydig's 

 and Mingazzini's observations ami ranges himself with Mingazzini, it 

 appears that he did not exanune the gall bladder of Raja bails, and the 

 general statement that "the stria^ are common to all" seems to me too 

 vague to warrant the fusion of 2 such distinct spore forms as those here 

 sei)arated as Chloromyxum leydigii and G. ineisum. Until distinct and 

 detailed comparisons between the spores habitant in the gall bladder 

 of Raja batis and those habitant in the gall bladders of the other 

 Plagiostonies shall have been made and properly recorded, the specific 

 identity of the 2 forms can not be admitted. 



Myxosporidium? — Examined in the bile the}' have the form of true 

 plasmodes, consisting of a diversely ramified, yellow globular proto- 

 plasm, movements exceedingly slow. A few minutes after being placed 

 on the slide they suddenly undergo modifi(;ation, throwing out an 

 external layer of colorless refracting protoplasm, wdiich (especially at 

 the extremities of the individual) suddenly ijrotrudes filiform thin 

 pseudopodia, which soon become more robust. They also nuxlify tlieir 



' In this connection the fllowing judicious criticism of Pt^ru^ia's upon Mingaz- 

 zini's work may be <inoted : "He had an opportunity to make interesting observa- 

 tions, but he might well have set them forth in greater detail in his papc^r, especially 

 as regards the various ])hascs of ibriiudion of the spore, whirh \u- affirms ho ob- 

 R-rved taking ])lace iu the vacuoles designated by Leydig as daugliter-cclls" [pau- 

 8])()roblasts]. 



^Bnll. Soc. idiilomat. Paris, 1892, IV, p. 176. 



= Desc I iption, M i nga /z i u i 's. 



