140 ILLINOIS BIOLOGICAL MONOGRAPHS [378 



which has no attachment to the subjacent connective tissue. It forms 

 a thin discoidal mass situated in the center of the concave surface of the 

 scale. The color of the mass slightly more yellowish than the surrounding 

 tissue, when coagulated. It is exceedingly difficult to detect its presence 

 in the fresh state. 



Spore: Elliptical, with the largest diameter passing thru two polar 

 capsules. Shell thin. Sutural edge narrow. Two polar capsules of equal 

 size convergent. Polar filament is extruded under the action of glycerine 

 and sulphuric acid. The vacuole in the sporoplasm is difficult to 

 detect. Sporoplasm also contains two nuclei, rarely one, 1 to l.S/i in 

 diameter. Dimensions: length 6 to 7/x, breadth 8)u. 



MYXOBOLUS OBESUS Gurley 

 [Figs. 419 and 420] 



1883 Balbiani 1883 : 203 



1893 Myxobolus obesus Gurley 1893 : 415 



1894 Myxobolus ? obesus Gurley 1894 : 239 

 1899 Myxobolus obesus Labbe 1899 : 100 

 1906 Myxobolus obesus Cepede 1906 : 60-61 



Habitat: On Alburnus alburnus L.; branchiae and kidney of A. lucidus 

 Heck. {A. mirandella BL); Lac du Bourget. 



Vegetative form: Balbiani gave no observation. 



Cepede observed as follows: Cysts, ovoidal, more or less elongated 

 or variable in form, not exceeding SOO/x in length. In kidney, numerous cysts 

 were of subspherical, ovoidal or rarely irregularly elongated form. Sub- 

 spherical cysts 500 to 600m in average diameter. Polysporous. 



Spore: Cepede describes as follows: Subcircular or ovoidal in front 

 view; lenticular in side view. Sutural edge exhibits variable numbers (4 

 to 5) of fold-like markings on the shell. Polar capsules pyriform and of 

 equal size. Coiled polar filament distinct. A small triangular intercapsular 

 appendix. Sporoplasm with a subspherical and clearly outlined vacuole 

 and two nuclei. Dimensions in vivo: length 11.5 to 12/x, breadth 7.5 to 8m, 

 thickness Sjx. Those of fixed and stained spores: length 11.25 to 11.50/i, 

 breadth 7.25 to 7.50)U, length of polar capsule 5^- 



Remarks: Cepede mentions that Alburnus alburnus L. mentioned by 

 Gurley is "without doubt" identical with A. lucidus Heckel. 



MYXOBOLUS CYCLOIDES Gurley 



[Fig. 421] 



