232 BULLETIN OP THE BUREAU OF FISHERIES. 



Diameter of spores 7-ioju, averaging about S/x; capsules 2^2.^11 by 4-5;^. 



Habitat. — Common in the urinary bladder of Opsaus iau. Foimd in 9 out of 1 1 fishes examined during 

 June and July. Both vegetative and sporulating trophozoites were abundant. 



Remarks. — The trophozoites are usually attached to the urinary epithelium, which in badly infected 

 fish may be almost entirely covered with them. The younger trophozoites are attached to the free ends 

 of the epithelial cells (fig. 93), which, however, show no signs of injury. As the trophozoites increase in 

 size they come to lie in depressions formed by the destruction of the ends of epithelial cells (fig. 94). 

 Often the injury to the epithelial cells is carried much farther than shown in the figure, in some cases the 

 part of the cell immediately surroimding the nucleus being all that is left, but even in such cases the 

 nucleus shows little signs of injury. In the larger trophozoites the basal portion becomes specially modi- 

 fied to form an organ of attachment. The protoplasm in sections appears much more densely granular in 

 this region than elsewhere and stains more deeply with plasma stains. Sometimes the organ is drawn out 

 into long processes which extend in between the epithelial cells. 



'' Genus Sinuolinea, new genus. 

 Sinuolinea dimorpha (Davis.) (PI. xxii, fig. 95-100.) 



Spharrospora dimorpha Davis 1916. 



Trophozoite. — Occurs in two very distinct forms, one disporous, the other polysporous. 



Vegetative disporous trophozoites colorless, transparent, irregular in shape (fig. 95); progressing by 

 slow amoeboid movements. WTien attached to the epithelium of the iu4nary bladder they are usually 

 rounded with one to several pseudopodia extending in between the free ends of the epithelial cells. 

 Ectoplasm distinct, forming a homogeneous hyaline layer around entire trophozoite. Endoplasm 

 filled with indistinct vacuoles separated by a denser homogeneous protoplasm similar to the ectoplasm 

 in appearance. Endoplasm usually contains a few small fat globules, which are more abundant in 

 older individuals. Occasionally the endoplasm contains one or more erythrocytes. 



Average diameter of full-grown disporous trophozoites about 25-30M. 



The polysporous trophozoites have a very characteristic appearance and can be readily distin- 

 guished from the disporous form in all but the youngest stages. When attached to the urinary epithe- 

 lium the free end of the body is drawn out into a long, cylindrical, taillike process (fig. 97). The body, 

 except where attached to the epithelium, is covered with numerous short, hairlike ectoplasmic proc- 

 esses, which are longer and more abundant toward the free end. While not movable, these processes 

 are readily absorbed and reformed. The trophozoites are attached to the epithelium by means of a 

 specially modified part of the ectoplasm, which forms irregular, thin, platelike processes extending in 

 between the outer ends of the epithelial cells. Owing to the viscid character of the ectoplasm, the 

 trophozoites are often completely covered with extraneous particles of various kinds. After being 

 placed on the slide the specially modified ectoplasm at the larger end gives rise to numerous conical or 

 arborescent pseudopodia, by means of which the trophozoite progresses slowly, the enlarged basal part 

 of the body becoming the anterior end. Pseudopodia are at first composed entirely of ectoplasm, but 

 later as they increase in size the endoplasm may extend into the proximal portion. In extreme cases 

 after being on the slide for some time almost the entire substance of the trophozoite may flow into the 

 large branched pseudopodia (fig. 98). Endoplasm distinctly granular amd usually more or less vacuo- 

 lated; numerous small fat globules usually present and are often very abundant in enlarged basal or 

 anterior part of body (fig. 96). In addition to fat globules, small, irregular, refractive granules and 

 occasionally a few yellowish crystals (probably hcmatoidin) can be seen in the endoplasm. These 

 crystals are never abundant and are entirely lacking in the majority of trophozoites. Endoplasm also 

 sometimes contains erythrocytes in various stages of disintegration. Very often several comparatively 

 large, rounded bodies can be plainly seen in the endoplasm. These are the gemmules, and each is com- 

 posed of an outer hyaline layer sturounding a finely granular central portion containing numerous 

 refractive granules. 



The size of polysporous trophozoites varies within wide limits. The largest trophozoite measured 

 was 575M long with a maximum diameter of 90M. 



Spore. — Approximately spherical. Sutural line forming a prominent sinuous ridge around spore 

 (fig. 99, 100). Capsules nearly spherical, large, conspicuous. Sporoplasm forming a distinct, rounded, 

 granular mass. 



Diameter of spore about i5;i; diameter of capsules 4.5M; length of filaments 27-35;^. 



