THE SPOROZOA 



287 



within the pansporoblast envelope (Fig. 96), and become straightened 

 out when set free from it. 



The polar capsules are fixed to the valves of the spore-membrane 



Fio. 94. 



Abnormal spore of 

 Ceratomyxa truncata, 

 Thel. (par. Clupea pil- 

 chardus), with three 

 polar capsules and 

 three valves, after 

 Thelohan. s, suture. 



Fio. 95. 



Spores of Sphaeromyxa balbmnii, 

 Thel. (par. Motetta and Cepda), 

 X 1500, after Thelohan. a, in the 

 fresh condition ; 6, fixed and stained, 

 showing nuclei, p.c, polar capsules ; 

 n.p.c, nuclei of polar capsules ; n.sp, 

 nuclei of sporoplasin. 



close to the suture, and communicate each with the exterior by a 

 fine canal, through which the coiled thread in the interior of the 

 capsule can be shot out (Fig. 97). The natural stimulus which effects 



FIG. 9(1. 



Two sister spores of Cerato- 

 myxa linospora, Dofl. (par. Labrus 

 turdus), still enclosed in envelope 

 of the pansporoblast, showing 

 the manner in which the long 

 processes of the spore are curled 

 round within the envelope. 

 (After Doflein.) 



the discharge of the polar capsules 

 is found in the digestive juices 

 of the specific host infected by 

 the parasite (see below, p. 290), 

 but the same result can be 

 brought about artificially by a 

 number of reagents, such as ether, 

 glycerine, boiling water, various acids, etc. When there is 

 only one polar capsule, it marks a point commonly termed an- 

 terior. When there are two capsules, they may either be close 

 together at the anterior pole, as in Myxobolus, etc. (Fig. 99), 



Fio. 97. 



Polar capsules of Myxobolus ellip- 

 soides, to show the ejection of the 

 filament. (From Wasielewski, after 

 Balbiani.) 



