158 ILLINOIS BIOLOGICAL MONOGRAPHS [396 



Vegetative form: The cysts are mostly spherical in form, and are 

 covered by a tough resistant envelope composed of the connective tissue 

 of the host. They are uniformly white in color, and have the variable 

 dimensions of from 0.5 to 1.5mm. in diameter. In section, the protoplasm 

 shows a coarsely reticulated structure without distinct differentiation. 

 In all cysts of various sizes fully mature spores were only observed. The 

 spore formation could not be worked out. Polysporous. 



Spore: Broadly oval with a slightly truncated anterior end in front 

 view (Fig. 628), lenticular in side or end view (Fig. 629). No intercapsular 

 appendix is seen. The shell is rather thick, and shows about eight folds 

 on the sutural edge, two of which located laterally being more conspicuous 

 than others. The sutural ridge is rather fine. Two convergent polar 

 capsules equal in size occupy the anterior half of the spore. The coiled 

 polar filament becomes more distinctly visible with the addition of Lugol's 

 solution, altho it is faintly observable in fresh state. Fresh spores ex- 

 truded their polar filaments under the action of potassium hydrate solu- 

 tion. In some spores, the extruded filaments cross each other near the 

 foramina. The preserved spores showed no extrusion of the filament 

 as in the last species. The sporoplasm is extremely finely granu- 

 lated. The iodinophilous vacuole is comparatively large. When stained, 

 the spore shows two nuclei in the sporoplasm. Dimensions of fresh 

 material: length 10 to 11.5jli, breadth 8.5 to 9.5m, thickness 6.5ai, polar 

 capsule 4.75m by 1.5 to 2n, length of polar filament 32 to 40^. Average 

 dimensions of unstained preserved spores: length 9.5/*, breadth 8m, polar 

 capsule 4.75 m by 2m. 



Remarks : The habitat and the structure of the spores, lead the writer 

 to record the species as a new species. 



Genus HENNEGUYA Thelohan 

 1892 Henneguya Thelohan 1892 : 167, 176 



1895 Henneguya Th61ohan 1895 : 352 



The characters of the genus are described on page 59. 

 Type species : Henneguya psorospermica Thelohan. 



HENNEGUYA PSOROSPERMICA Thelohan 

 [Figs. 486, 487 and 496] 



Habitat: Branchiae of Esox lucius L. and Ferca fluviatilis; France, 



