3371 STUDIES ON MYXOSPORJDJA—KUDO 99 



independent openings at the anterior end. Coiled polar filament indis- 

 tinct. Abnormal spores with five polar capsules are sometimes seen. 

 Dimensions of fixed spores: length 8/x, breadth 7/i, thickness 5 to 6m, polar 

 capsules 2 to 2.5/x by 1.5/i. 



CHLOROMYXUM WARDI nov. spec. 

 [Figs. 632 to 642] 



Habitat: In the gall-bladder of Oncorhynchus nerka: Klutina Lake, 

 Alaska (August). A single gall-bladder collected and preserved in formol 

 by Professor Ward, was found to harbor the present species. The study 

 was done on preserved material and on stained smear preparations. 



Vegetative form: Young trophozoites (Fig. 632) show ameboid form, 

 and are mostly multinucleated. The protoplasm is not well diflferentiated 

 either in unstained material or in stained specimens. It is granulated 

 thruout the body, and is vacuolated at places. The smallest form mea- 

 sured was 18m in largest diameter. The shape of the body suggests its 

 possession of ameboid movements when alive, altho the writer could not 

 examine fresh specimens. Large trophozoites in which the spore forma- 

 tion had partly been completed are generally rounded with reticular proto- 

 plasm. Size varies to some extent. The trophozoite shown in figure 633 

 contains six mature spores and is 23fi in largest diameter. The largest 

 one found was 38 by 30/x, showing ten spores and nuclei. Each spore 

 appears to develop independently from a single sporoblast. Disporous 

 and polysporous. 



Spore: Rounded pyramidal in front view (Figs. 640 and 641); circular 

 in transverse section (Fig. 638). The shell is thickened near the posterior 

 margin (Figs. 640 and 641). Sutural line is not straight, the ridge being 

 fairly distinct. The striations on the shell vary to a considerable extent 

 (Figs. 634 to 637 and 639). Four polar capsules at the anterior end, 

 mostly unequal in size and shape. The coiled polar filament is invisible 

 in formol material. Potassium hydrate solution does not cause its extru- 

 sion in the preserved spores. The sporoplasm is finely granular with two 

 nuclei. Dimensions of unstained preserved spores: diameter 7.5 to 9n, 

 polar capsule 3 by 2.5^. 



Remarks : The writer was able to study forty specimens of gall-bladder 

 of Alaskan fishes, chiefly of salmon, which have been collected by Professor 

 Henry B. Ward, during the summer of 1919, for which he wishes to express 

 his deepest appreciation. The examination of these specimens showed 

 that myxosporidia were found only in one of the gall-bladders, and that 

 specimen presented a fairly heavy infection of the present species. 



Family SPHAEROSPORIDAE Davis 

 1917 Sphaerosporidae Davis 1917 : 219 



The characters of the family are described on page 57. 



