I 



SPOROZOA OF THE FISHES OF THE ST. ANDREW'S REGION 31 



SESSIONAL PAPER No. 39b 



endoplasm. In the living parasite the ectoplasm is hyaline, the intermediate 

 zone very finely granular and slightly less transparent than the ectoplasm while 

 the endoplasm is filled with yellowish green granules (Fig. 2, c). In stained 

 preparations this differentiation of the protoplasm becomes more apparent, the 

 intermediate zone being more deeply stained than either the ectoplasm or endo- 

 plasm (Fig. 2, a and h). The nuclei are confined to the endoplasm. The pseudopodia 

 may be of two forms: — lobose, relatively large and rounded (upper and left side of 

 Figure 2, b) or fine and short in which case they are usually numerous and arranged 

 so as to give the part of the surface where they occur a villate appearance (right 

 of Fig. 2, b). The latter attach the myxosporidium to the epithelium of the gall 

 bladder. Under certain conditions the myxosporidium may become surrounded 

 by a distinct doubly contoured membrane (Fig. 2, c) giving the whole the appear- 

 ance of a cyst. At times the protoplasm may be seen in fresh preparations to be 

 shrunken within this membrane leaving a clear space between the membrane and 

 the ectoplasm. The sporoblasts are formed without the previous formation of pan- 

 sporoblasts. One to six sporoblasts may be found in a myxosporidium. The 

 sporoblasts are usually not arranged in pairs but are scattered in the myxospori- 

 dium. Figure 2, b, shows a myxosporidium with one sporoblast. The sporoblast 

 shows the usual six nuclei: — the two nuclei of the valve cells, the two of the 

 capsulogenous cells, and the two germ nuclei. The two nuclei of the valve cells 

 will be seen each to have adherent to the periphery at one point a dark body. 

 This dark body seems to be of frequent or constant appearance at this point. 

 Its significance is not clear to the writer. A later stage where the polar capsules 

 are forming is shown in Figure 2, d. Here also there are two germ nuclei. In 

 every spore examined from the gall bladder there were two germ nuclei. 



The spores are spindle shaped with the axis of the spindle slightly bent 

 in the form of an enlongated S, the two ends of which have been bent at right 

 angles to the plane of the letter and in opposite directions. Corresponding to 

 this curving of the axis of the spindle, the polar capsules are placed with their 

 axes approximately tangent to the curve described, i.e., their axes make angles 

 (of about 20°) on opposite sides of the line joining their points of contact with 

 the spore shell. The polar filaments are visible within the capsules in the fresh 

 state but the number of coils of the spiral in one capsule could not be counted. 

 The filaments were not extruded when treated with a solution of iodine in potassic 

 iodide. The dimensions of a typical spore are: 



Length 16-18 fx. 



Width 6-7 fx. 



Length of polar capsule 4 n. 



Width of polar capsule 2 • 5-3 m- 



This description will be found to agree with that of Auerbach ('09, '09* p. 61, and 

 '12, pi. 2), in all particulars with the exception of the cyst-like condition described 

 in the present paper. The presence of this cyst may however be due to some 

 exceptional condition of the parasite. 



