144 ILLINOIS BIOLOGICAL MONOGRAPHS [382 



MYXOBOLUS NEUROBIUS Schuberg et Schroder 

 [Figs. 433 to 436] 

 1905 Myxobolus neurobius Schuberg and Schroder 1905 : 49-56 



Habitat: Nervous tissue of Trutta fario L.; Gutach (May?). 



Vegetative form: Cysts, usually elongated, often spherical. Elongated 

 form 0.9mm. by 0.02mm. The seat of the cysts is between the medullary 

 sheath and sheath of Schwann. Neither medullary sheath nor axis-cylinder 

 was infected. Cyst-membrane could not be made out. Cysts contained 

 only full-grown spores without any younger stage. Polysporous. 



Spore: Broad oval in front view; spindle shaped in side view. Anterior 

 end attenuated, posterior end rounded. Shell somewhat thick. Sutural 

 ridge is not particularly marked. Edge without any fold. No intercapsu- 

 lar appendix. Sporoplasm, with a large and spherical iodinophilous 

 vacuole and a single nucleus, occupies less than one half of the inner space 

 of the spore. Two polar capsules, pyriform, fuse into one at the anterior 

 end. Coiled (8 to 10 times) polar filament distinct. Dimensions: length 

 10 to 12/i, breadth 8)u, thickness 6)u, polar capsule 6 to 7^ by 2/i. 



MYXOBOLUS AEGLEFINI Auerbach 

 [Figs. 437 to 441] 



1906 Myxobolus aeglefini Auerbach 1906 : 568-570 



1906 Myxobolus aeglefini Auerbach 1906a : 115-119 



1907 Myxobolus esmarkii Johnstone and 1907 : 204-208 



Woodcock 



1909 Myxobolus aeglefini Auerbach 1909 : 76-78 



1910 Myxobolus aeglefini Auerbach 1910c : 181-182 



1911 Myxobolus aeglefini Nemeczek 1911 : 162 



Habitat: Cartilage and bone of cranium and eye of Gadus aeglefinis 

 G. callarias, G. merlangus L., G. morrhua L., G. esmarkii and Molva vulgaris 

 Flem.; Norway, Morecambe (March). 



Vegetative form: Cysts in cartilage and bone of cranium and in carti- 

 lagineous layer of the sclerotic of the eye. Protoplasm is distinctly 

 differentiated. Ectoplasm somewhat vacuolated; endoplasm granular 

 with numerous small nuclei. Polysporous. 



Johnstone's observations are as follows: Round the peripheral part 

 of the cornea, and covered loosely by conjunctiva are a number of milk- 

 white rounded or oval bodies, from about 1 to 3mm. in diameter. Several 

 of these fused to form elongated mass which lie along the curvature of the 

 periphery of the eye. These cysts also invade the lateral and posterior 

 parts of the bulbus oculi. In sections, the cysts lie within the thickness 

 of cartilaginous layer of the sclerotic. This latter is enlarged into thick 

 layer (2mm.) by the presence of the cysts. 



Nemeczek mentions irregular cysts of 1.5mm. in diameter. 



