132 ILLINOIS BIOLOGICAL MONOGRAPHS [370 



MYXOBOLUS sp. Kudo 

 1918 Myxobolus sp. Kudo 1918 : 15 



Habitat: Spleen of Perca flavescens; West Falmouth, Mass. (August). 

 Isolated spores were noticed in one fish, in smears and section preparations. 



Vegetative form: Not observed. 



Spore: Ovoidal, attenuated at the anterior end. Shell uniformly thick. 

 A single polar capsule opens at the anterior tip. Sporoplasm contains an 

 iodinophilous vacuole and two nuclei of equal size (2/x). Dimensions: 

 length 18 to 20/x, breadth Sfx, polar capsule 7 to 9^ by 3 to 6/x. 



MYXOBOLUS ROHITAE Southwell et Prashad 



[Figs. 373 to 374] 



1918 Myxobolus rohitae Southwell et Prashad 1918 : 344-347 



Habitat: Branchiae of Labeo rohita; Turag river, Mirpur, Dacca 

 district, Bengal (June). Type specimens of Indian Museum P48/1. 

 Infection was heavy. In one case 53 cysts were found on one surface of 

 a single gill. 



Vegetative form: Cysts in the gill-filaments. The cysts preserved in 

 alcohol are of a creamy-yellow color, oval to cylindrical in form, lying with 

 the long axis parallel to the gill-filaments. Cysts attached to the gill- 

 filaments with the flattened surface. Size: length 3.1 to 3.8mm.; breadth 

 0.8 to 1.2mm. Cyst-wall striated vertically, covered with an epithelium, 

 two to three layers thick. In the central portion and at the periphery, 

 mature spores and pansporoblasts as well as immature spores were found 

 respectively. Polysporous. 



Spore: Elongated pyriform, rounded at the posterior end and acutely 

 pointed anteriorly. Sutural ridge slightly raised. One polar capsule 

 present, being of conspicuous size. Coiled polar filament is distinctly 

 observed in the polar capsule. An iodinophilous vacuole, 3.6ju in diameter, 

 in the sporoplasm. "Lying just posterior to it is the nucleus of the spore. 

 A few granules of chromatin were also seen lying scattered in the proto- 

 plasm." Dimensions: length 30 to 32^*, breadth 7 to 8m, length of the polar 

 capsule 22 to 23^, that of polar filament 92 to 97/x. 



MYXOBOLUS SENT Southwell et Prashad 



[Figs. 375 to 376] 



1918 Myxobolus sent Southwell et Prashad 1918 : 347 



Habitat: On the median and caudal fins of Labeo rohita; Mirpur, 

 Dacca (January). Type specimens in Indian Museum numbered P 53/1. 



Vegetative form: Trophozoites form cysts which are elongated ellip- 

 soidal. Size from 4.7mm. to 5.4mm. in length, 2.9mm. to 3.7mm. in 



