7-i MEMOIES OF THE UNIVEKSITY OF CALIFORNIA 



In some cases the cyst may reach relatively enormous proportions, and 

 secondary (pi. 8, fig. 89), or even tertiary (pi. 5, fig. 54 ; text fig. Q, 7) cysts may 

 be formed within the first one. 



Some time before the organism breaks out of the cyst new flagella make 

 their appearance. These at first are very short (pi. 8, fig. 85), but reach their 

 normal length before the ruj)ture of the cyst wall (pi. 8, fig. 87; pi. 9, fig. 101). 

 "With the development of its motor organelles the minute organism usually be- 

 comes active, rotating in the cyst with nearly constant movement of the flagella. 

 In one instance Cochlodiiiiitm jnr'uui (pi. 9, fig. 101) was held under observation 

 for several minutes before it escaped from the cyst, the size of which allowed 

 gi"eat freedom of motion. Its behavior was quite similar to the activities of a 

 small animal suddenly placed in a cage for the first time. It swam round and 



Fig. P. 1. Encysted Pouchetia rubescens sp. nov. X 700. Food body present. Secondary cyst formed. 

 This became ruptured and gradually shrank away to one side of the enclosed organism. 2. Encysted Nemato- 

 dinium partitum sp. nov. X 710. 



roimd the cyst with the apex almost touching the wall Init apparently '\\'ithout 

 exerting any pressure upon it, though the final result was the same as would 

 have occurred had actual pressure been exerted, that is, the wall suddenly burst 

 and the flagellate escaped from its prison. 



Irregularities in the shape and size of the cyst may sometimes occur, though 

 not so frequently as might be expected in these delicate organisms. The unusual 

 cyst enclosing Gyroclinuim caudatum (pi. 9, fig. 102) may be due to some ab- 

 normality, but more likely it corresponds to the secondary cyst shown in text 

 figures I, 5, 6, 7. in which a single individual onlv has been developed (cf. pi. 2, 

 fig. 14). 



As may be seen from figure Q, three kinds of cysts are formed. The large 

 globular cyst (fig. Q, 2) and the crescent-shaped ones are more resistant than the 

 others. The former is probably the resting stage of the organism. These are 

 frequent in preserved material and sometimes abundant. 



The second t^i^e of cyst, which is also highly resistant, is the crescent-shaped 

 one. The wall of this is usually double-contoured and much thicker than the 



