THE MYXOSPORIDTA, OR PSOROSPERMS OF FISHES. 213 



of tlic Ividnoy of Tinea tinea L. (tench). He farther asserts that the same 

 form is found on the branchire, but as he does not figure any si)ores 

 from the hist seat it may perhaps be a question wliether the branchite 

 yiehl tlie present species in addition to M. piriformis. 



In the kidney a 3-chambered pigment cyst was seen 27 // (gV") 

 long, the end compartments of which were occupied by pigment and the 

 central one by a pyriform spore.' The piginent-follicles of the spleen 

 almost always contain untailed psorosperms in considerable numbers, 

 lying without order between the ])igment-hokling cells. The pigment 

 follicles of the kidneys always contain the same species as that found 

 in the spleen and upon the gills (liemak). 



38. Myxobolus? sp. incert. PI. 14, fig. 4. 



Psorosperms of Cyprinits tinea, Lieberkiilui, 1854, Miiller's Arohiv., pp. 6,24, 

 353, pi. 2, figs. 21-27. 



Lieberkiihn's description is substantially as follows: 

 Cyst imbedded in cornea immediately under the inner surface. Upon slight pres- 

 sure very many spores, partly with and partly without tail-like appendages, and 

 whose shell was no longer smooth but wrinkled, and whose capsules were no longer 

 together biit occupied unusual positions, were seen. Individual shells contained 

 only 1, and others no cnpsule. A number of free " nuclei " which had preserved the 

 club-shape of those within the spore also were seen. Finally, very small diaphanous, 

 nongranular, amoebiform corpuscles occurred, which plainly, though slowly, moved 

 with blunt or sharp processes. 



Habitat. — Encysted in cornea of Tinea tinea L. (tench). 



Concerning these figures, Thelohan (letter to author, 1893) says that 

 they are not to be approximated to M. iJiriformis. Lieberklihu's fig. 21 

 would, he says, rather suggest Chloromyxum dujardini. 



39. Myxobolus? mugilis Perugia, 1891. PI. 14, figs. 5, 6. 



Myxosporidium m«^i7(s Perugia, Boll. Scientif., Pavia, xiii, pp. 23-24, plate, figs. 



7, 8 ; i&., Weltner, 1892, Sitzungsber. Gescllsch. Xaturf. Frounde Berlin, p. 35. 

 Myxoholus mugilis Thdlohan, 1892, Bull. Soc. philomat. Paris, iv, p. 166; ib., 



Gurley, 1893, Bull. U. S. Fish Com. for 1891, xi, p. 414 ; ib. Braun, 1894, 



Centralbl. f. Bakt. u. Parasitenkde, xv, p. 87. 



Cyst membrane. — Having removed with care one of the cysts from 

 the branchifc of ilf. eapiio, Perugia observed it to consist of 3 (others 

 contain 2) separated myxosporidia surrounded by a common investing 

 membrane evidently derived from the branchial lamella, which latter at 

 no point showed any solution of its continuity. From this he concluded 

 that the cyst is a production of the host. Some cysts contain 2 or 3 

 myxosporidia filled with spores, and with a residue of a very few granu- 

 lations of protoplasm. 



Myxosporidium not described. 



Spore. — Free; " without a i)roper membrane " ^; length, 7//. 



Habitat. — Encysted in the branchial lamelhe of Mui/il ax rat us and of 

 M. eapito (gray mullets). Kare; found only twice in 300 JMugils. 



' Remak here erroneously refers to his fig. 5a instead of fig. 7A. 

 'From other similar expressions by the same autlior 1 interpret this to mean: "No 

 pansporoblAst meinbran«." 



