150 PROCEEDINGS OF THE ACADEMY OF [PaRT I 



wasserflora," p. 5) refers: "In some particular groups (Crypto- 

 monadinae), springing movements are effected by sudden contrac 

 tions." 



This explanation, which seems to be commonly accepted today, 

 but without anybody trying to prove the fact, has in my opinion 

 hardly any probability. If we take a frog, for instance, and cut 

 its four legs quite close to the body, how can we imagine it to make 

 sudden leaps two and three yards distant, by means of a contraction 

 of its body? Our Cryptomonas, after all, very much resembles a 

 frog, and even supposing its whole body to be contractile, it would 

 be difficult to explain in this way even a mere trifling displacement. 

 Such general contractility in Cryptomonas is, besides, nothing but 

 a supposition, I don't think any observer ever noticed any contrac- 

 tions, and for my part, I could find no sign of contractility at all. 

 But even supposing the contractility to exist, the solution of the 

 question would not be much advanced, I happened on several occa- 

 sions to see the animalcule leaping, for one or two seconds at least, 

 when (under the influence of a current of glycerine) the ectoplasmic 

 layers of the body were already crumpled, inert and dead. Crypto- 

 monas, in fact, jumps after death. 



In short, the contraction theory remains a mere supposition, 

 and I may feel entitled to propose another explanation, which, if 

 not necessarily certain, seems based at least on real phenomena. 

 But before developing the subject, I must state a fact, which does 

 not seem to have been mentioned yet: beside these long leaps 

 backward, other leaps may be seen to occur, even much more fre- 

 quent, but of much less importance; the body becomes displaced 

 to right or left, forward or backward, by very slight quiverings, 

 and the same appearance is noticed as in Infusoria while they are 

 discharging their trichocysts. Now we have seen that according 

 to the researches of Belar and others, the very tiny granules that 

 are found in the periplast of Cryptomonas may be considered as 

 trichocysts; in fact, one might compare them also to the "slime 

 trichocysts" which we shall later on speak of in Trentonia flagellata; 

 and it can hardly be doubted, I think, that the sUght quiverings in 

 Cryptomonas are due to superficial trichocysts also. 



My supposition, then, could be formulated in the following words : 

 the sudden jumps backward are due to the explosion of big tricho- 

 cysts, and these are represented by the granules which line the 

 pharyngeal cavity. 



