THE MYXOSPORIDIA OF THE BEAUFORT REGION. 



211 



at the end of the duct. In spores containing two capsules the filaments in each are always 

 coiled in opposite directions — i. e., one is the mirror image of the other. Under suitable 

 stimulation the filaments are everted through the pores in the sporocyst in much the 

 same way as in the case of the coelenterate nematocyst. The sporoplasm {sp'p.) is 

 a finely granular, translucent mass of protoplasm, which commonly fills most of the 

 space within the sporocyst not occupied by the capsulogenous cells. In the fully 

 matured spore, expecially after it has left the body of the host, the sporoplasm may 

 become rounded. It is usually situated in the middle of the spore, extending equally 

 into both valves, but in some cases (many Ceratomyxa) may be unsymmetrically located, 



s.l. fii. 



'"^P-,cap.c. 



Fig. 2. — Structure of myxosporidian spore based primarily on Leptoiheca. A, viewed from above; B, viewed 

 from the capsular side; C, viewed from one end; A-B, longitudinal axis; C-D, transverse axis; E-F, vertical 

 axis; cap., capsule; cap. c, capsulogenous cell; fil., filament; par. n., nucleus of parietal cell; s. I., sutural line; 

 sp^c, sporocyst; sp'p., sporoplasm; sp. n., nuclei of sporoplasm, 



sometimes being confined entirely to one valve. Within the sporoplasm are two nuclei 

 {sp. n.), which usually He close together, often in contact. In addition to the nuclei 

 there are often several small, fat globules present and in the Myxobolidae the char- 

 acteristic " iodinophilous vacuole," which is probably composed of glycogen. The 

 liquid-filled space (pericystic space) within the spore not occupied by either the cap- 

 sulogenous cells or sporoplasm often contains numerous granules and small fat globules. 

 The spore is usually bilaterally symmetrical, the sutural plane forming a plane 

 of symmetry, but to this rule there are numerous exceptions, and in a few cases the 

 shape of each valve of the sporocyst is quite different. 



