148 ILLINOIS BIOLOGICAL MONOGRAPHS [386 



Spore: Elongated oval. Two polar capsules, with 7 to 8 times coiled 

 polar filament. A triangular intercapsular projection. Sporoplasm with 

 an iodinophilous vacuole. Dimensions: length 10 to lO.Sju, breadth 8 to 

 8.5m, length of polar capsule 4.5ju. 



MYXOBOLUS CORDIS Keyssehtz 



[Figs. 460 and 461] 



1908 Myxobolus cordis Keysselitz 1908 : 279-282 



Habitat: Muscle of ventricle, rarely that of bulbus arteriosus of Barbus 

 fluviatilis Ag., spores found in kidney, liver and spleen in the condition of 

 somewhat scattered infiltration; Germany (Mosel and Neckar). 



Vegetative form: Elongated, oval, sausage or club form. The body 

 whitish, later yellowish. Size from 0.25 up to 4mm., usually 1 to 1.5mm. in 

 length. Propagative stage and cysts observed. One end of the body is 

 held more or less deeply in the muscle and is covered by cellular envelope 

 as in Myxobolus musculi, while remaining larger portion of the body is sus- 

 pended freely inside of the ventricle, covered with a thin layer probably of 

 endocardiac cells. Fish 30 to 45cm. long harboured 40 to 60 parasites. 

 No movements. Ultimately the cysts are formed with differentiated 

 protoplasm. Polysporous. 



Spore: Oval. Shell very thin at the anterior end. At the posterior 

 end, cell-like appendage, 2 to 3^ wide which is probably formed by both 

 valves, is present. Two pyriform polar capsules at the anterior end, which 

 show the polar filament coiled 7 to 8 times. Sporoplasm with a 

 comparatively large and oval iodinophilous vacuole and two nuclei, 

 rarely one (syncaryon). Dimensions: length 12/x, breadth lO^i, length of 

 polar capsule 4.5m- 



MYXOBOLUS MUSCULI Keysselitz 



[Figs. 462 to 464] 



1908 Myxobolus musculi Keysselitz 1908 : 282-286 



Habitat: Muscle of the main body, rarely that of fins and operculum, 

 Q,n6i^\dT\ty oi Barbus fluviatilis hg2is?>. of various size (youngest fish found 

 infected, 2 months old), spores in liver, spleen, kidney and ovary (not the 

 ovum) in diffuse infiltration; Mosel and Neckar. 



Vegetative form: Elongated. Body whitish opaque, with differentiated 

 protoplasm. Smallest individual observed, 24/i. Large form 2mm. in 

 length. Many trophozoites are found closely situated, forming a large 

 mass of parasites that reached dimensions of 4mm. by 2mm. The 

 surrounding envelope, varying in thickness, composed of cells with 

 elongated nuclei as those of perimysium. Young cysts surrounded by thin 

 layer of ectoplasm. Polysporous. 



