60 



MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



These were described by Biitscbli (1887-89) as occurring in pairs scattered 

 tlirougli the peripheral protoplasm. 



The only other organelles of a similar nature occurring outside the Cnido- 

 sporidia are the trichocysts abundant in many species of the Ciliata. These 

 are not characteristic flagellate structures. Both Chatton (1914c) and Faure- 

 Fremiet (1913) describe trichocysts in Polykrikos, however. These slender 



Fig. H. Trichocysts and nematocysts. 1. Exploded trichocyst of Frontonia leucas Ehrbg. After Tonniges 

 (1914, pi. 18, fig. 1). X 1250. 2. Unexploded trichocyst of same (pi. 18, fig. 4). X 1300. 3. Nematocyst of ff)/(ira 

 attenuatus. After Toppe (1910, pi. 14, fig. 45c). X ? 4. Exploded nematocyst of Hydra grisea. After Toppe 

 (1910, pi. 14, fig. 46b). X ? 5. Nematocysts of Myxobolus. After Doflein (1911, fig. 820 A). X ! 



refractive bodies or rodlets, as Ave have termed them, are found throughout the 

 genera Gymnodinium and Gyrodininm as well as Polykrikos. They seem to 

 have no resemblance, either in structure or function, to the trichocysts of the 

 ciliates. No evidence is forthcoming to link them with the developing nemato- 

 cyst. Their general occurrence in many species of two genera which do not 

 possess nematocysts would preclude the possibility of so classifying them. 



