192 LORANDE LOSS WOODRUFF AND HOPE SPENCER 



the depression there is a sht-hke opening into the endoplasm~ 

 It is impossible to determine the hmits of the opening except 

 when the animal is starting to feed, since at other times the 

 edges are closely appressed. However, when a small ciliate is 

 seized, it rapidly opens and the prey is forced in by means of 

 the contractile edges of the cytostome, assisted apparently, in 

 the earliest stages, by the activity of the larger cilia in this 

 region. 



Trichocysts. Maupas and Moody describe a row of minute 

 rod-like bodies near the edge of the peristome. Maupas gives 

 no details in regard to these bodies, apparently taking it for 

 granted that they are trichocysts. But Moody definitely states 

 that ''Three artificial methods were used to explode the tricho- 

 cysts : exposure to osmic acid vapor, treatment with a 2 per cent 

 solution of acetic acid and a solution of methyl green. After 

 treatment with any one of these reagents, in fifty individuals 

 examined, the cilia were found freely extended, the trichocysts 

 being readily distingaiished from the long oral cilia inasmuch 

 as they were straight and stiff in appearance, whereas the cilia 

 showed a wavy outline." This statement seems to be sufficiently 

 positive to settle the question, though farther on in the same 

 paragraph the author states that she has not ''found the greatly 

 elongated trichocysts of complicated structure described by 

 Maier, Schuberg, and Schewiakoff for Frontonia, Paramecium 

 and other ciliates; owing, however, to the paralyzing effect on 

 Colpidium following contact with the anterior end of the body, 

 I think it safe to interpret, as trichocysts, the short opaque 

 rods so plainly visible in the thickened rim of the mouth." ^ 



We have been unable to demonstrate the extrusion of tri- 

 chocysts in our material, although we have tried all the methods 

 which are effective in other ciliates, such as Paramecium, in- 

 cluding the reagents used by Moody herself. In favorable 

 specimens the basal granules of the oral cilia can be seen and 

 present somewhat the appearance of 'trichocysts' as shown in 

 Moody's figure 12. However, they are identical in structure 

 with the basal granules of the smaller cilia on the general surface 



* Loc. cit., p. 356. 



