THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 2Gl 



structure of the spore, viz, " ItvS tliecUi sIioavs au obli(|ue striatiou in 

 two contrary directi()]is." Moreover, lie unfortunately fails to indicate 

 the species of fishes which he examined.' 



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

 iued, which includes 2 species investigated by Le\^dig. He says: 



While l^eydig had observed that CvTtaiu sjiores were striated and others not, 

 Minsazztui says that the striie are coiiiniou to nil, and is of opinion that there is 

 question of but a single species, an o))iui()u whicli I believe to be correct. 



In describing GhJoromyxum l('i/di;/ii, Thi'lohau^ says it has 



Great stria' upon the shell, which, in passing round tlie posterior part of the spore, 

 give it a toothed appeiirance. 



It is tlius evident that he includes with the present species (J. incisum. 

 As there is nothing, however, anywhere iu the literature to show that 

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

 this statement is oidy intended as representing the consensus of opinion, 

 that is, Mingazzini's and Perugia's views. 



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

 examined tlie gall bladder of K<ij<( hatis, and (2) only the very loose 

 statement given above (which practically amounts to nothing), so that 

 his oi)iniou that there is but one species is a mere dictum, and even that 

 does not necessarily, as far as the record shows, refer distinctly to this 

 case. 



Further, although Perugia notes the discre[>an('y l)etween Leydig's 

 and Mingazzini's ob.servations and ranges himself with Mingazzini, it 

 appears that he did not examine the gall bladder of jK<yV( hatis, and the 

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

 vague to warrant the fusion of 2 such <listiuct spore-forms as those here 

 separated as Gldoromyxum Ici/digii and G. inci.sioii. Until distinct and 

 detailed comparisons between the spores habitant in the gall bladder 

 of Eajn hatis and those habitant in the gall bladders of the other 

 Plagiostomes shall have been made and i)roperly recorded, the specific 

 identity of the 2 forms can not be admitted. 



Mijxosporidium? — Examined in the bile they 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 modification, throwing out an 

 external layer of colorless refracting protoplasm, which (especially at 

 the extremities of the individual) suddenly jirotrudes filiform thin 

 l)seudopodia, which soon become more robust. They also nu)dify tiieir 



' In this connection the fdlowing judicious criticism of Perugia's upon Mingaz- 

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

 tions, but he might well have set them forth in greater detail in his paper, especially 

 as regards the various phases of formation of the spore, which he affirms he ob- 

 ssrved taking place in the vacniolos designated by Leydig as daughter-cells'" [pan- 

 sporoblasts]. 



•^Bull. Soe. philomat. Paris, 1892, iv, p. 176. 



- Description, Mingazzini's. 



