MORPHOLOGY AND PHYSIOLOGY 



33 



known as the trichocysts (Fig. 13), which are apparently defen- 

 sive cell-organs. As seen in a living Paramecium, the refractile 

 trichocysts are embedded in the ectoplasm and arranged at right 

 angles to the body surface. Each trichocyst is a spindle-shaped 

 body with a round end which is prolonged into a fine projection 

 facing the body surface. Trichocysts take a nuclear stain in- 

 tensely. Brodsky (1924) believes that they are made up of 

 colloidal excretory substances and are first formed around the 



Cilia 



Pellicle 

 Basal granule 

 Ectoplasm 

 Trichocysts 

 Roots of cilia 



d ^ 



Trichites 



Fig. 13 a. Portion of section of Paramecium caudatum showing ectoplasmic 

 structure. X1530. 



b. Two completely extruded trichocysts of Paramecium caudatum. 

 X1530. 



c. Spathidium spatula as seen in stained section, showing trichites. 

 X200 (After Woodruff and Spencer). 



d. Enchelyodon farctus from life. X about 180 (After Blochmann 

 from Doflein). 



