THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 303 



Plate 43. 



Figs. 1-5. Myxidium JieherkUhnii. 



1. Myxosporidia (iifter laeberkiilin. X 1). 



la. Showing the graiinle-free, pronged end by which attachment is eftected, 



and a panspoiolihist containing 2 spores. X 330. 

 lb. Myxosporidiuni which has mostly broken up into pansporoblasts. X 900. 



2. Specimen covered with transverse wrinkle-like elevations; atone end some 



psendopodia (alter lUitschli. X?). X 160. 



3. Three successive stages in the development of clear ectoplasmic psendopodia 



at one end of a large myxosporidium (after Biitschli. X 1). 



4. Small myxosporidium attached to a nucleated bladder cell (after Biitschli. 



X 1). 



5. Strongly amoeboid-branched specimen (after Biitschli. X t). X about 90. 



Plate 44. 



Figs. 1-5. Mifxidium lieberTculmii (after Biitschli. X 1). 



la,h. Large forking myxosporidia; a, with fine hair-like ectoplasmic pro- 

 cesses. 



2. Large myxosporidium, showing interlaminye between ectoplasm and endo- 



idasm. 



3. Portion of border of myxosporidium showing the peculiar canaliculate struc- 



ture mentioned on p. 285. 



4. Part of border of large myxosporidium -with branched horn-like ectoplasmic 



prof^esses. 

 ba-d. Four yellowish fat globules, inclosing hiematoidin crystals. 



Plate 45. 



Figs. 1-3. Myxidium lieherkiihnii (after Pfeiffer. X 1). 

 la. Smallest form. 

 lb. Small form with fat globules, haematoidin crystals, with only 1 pair of 



ripened spores; ectoplasm evident. 

 Ic. Motile myxosporidium with Very strong soap-bubble-like ectoplasm; in its 



interior a well-preserved red bloOd corpuscle, with fat globules and htema- 



toidin inclusions. 

 Id. Specimen with amnpboid pseudopodia. 

 le, /. Large forms with scattered spores. 

 1*7. Carmine staining after removal of fat by chloroform; the whole endoplasm 



riddled with nuclei. As yet without spores. 

 1/i. Isolated spore X 1200. 

 2,1. Superficial epithelial layer; 6 healthy epithelial cells with nuclei, and 2 



separate strongly hypertrophicd cells in which, very soon after infection, 



the nucleus is destroyed. 

 2, Ila. Myxosporidium fallen out of epithelial cell. Still without ectoplasm. 

 6. Young form, free in urine with ptu-uliar pseudopodioid motile ectoplasmio 



processes extruded and retracted on a slightly warm stage and many fat 



globules in the endoidasni. 



2, Ilia. Pansporoblast formation ; «, small myxosporidium with bristle processes. 

 b. Sexanncleate pansjioroldasts. which later form 2 trinucleaf(^ sporoldasts; 



in each sporoblast 2 nuclei form the cai'Sules, the third the sporoplasm (Jide 

 Pfeiffer). 



3. Transverse section of urinary bladder of pike, alcohol-hardened, celloidia- 



imbedded, hcenuitoxylin-stained. 

 3a. Showing, from right to left, tiie external muscle layer, the internal muscle 



layer cut transversely, the snbnnicosa, the epithelium with infection in the 



snperficial layers, and free brown-colored myxosporidia containing h;ema- 



toidin and sporoblasts. x 80. 

 Sb. Portion of a. To the right the moristrously ai)peariug myxosporidia and 



sporoblasts. X 400. 

 3o. Natural size of the bladder sectiou. 



