4 Invertebrate Zoology. 



Use dilute acetic acid, and note the form and arrangement 

 of the trichocysts, defensive bodies comparable to the nema- 

 tocysts of Ccelenterates. 



A ciliate infusorian contains a macronucleus and one or 

 more micronuclei. The former is a comparatively large 

 body and can readily be observed by the use of dilute acetic 

 acid. The micronuclei are smaller and, in some cases, diffi- 

 cult to find. 



ParamcKcia are often to be observed attached in pairs by 

 their vestibular surfaces, in process of conjugation. After 

 remaining attached for some little time, the two become 

 free and undergo division \>y fission. 1 



Make a drawing of Param(Kcium, naming the parts. 



1 Conjugation is completed by disappearance of the macronuclei, which 

 are supposed to be nutritive bodies for use during this period of inac- 

 tivity. The micronuclei, during conjugation, are actively dividing, and 

 previous to separation one of these divisions in each organism passes 

 over into the body of the other. 



