164 PROCEEDINGS OF THE ACADEMY OF [PaRT I 



When describing the thick layer of opalescent ectoplasm which 

 surrounds the body, I mentioned but two kinds of included ele- 

 ments, the tiny trichocysts and the small round vesicles; but we 

 must now consider a new sort of inclusions. They are spherules. 

 2^ in diameter, of a very pale and pure bluish hue, and though 

 extremely numerous, generally escape any notice, or rather are 

 ascertained onl}^ after compression of the body; and the greater 

 the compression the more numerous they are seen to be, they are 

 in such numbers, in fact, that they seem to make up the whole of 

 the plasma. 



Singly examined (Plate VTII, fig. 67a), they are seen to possess 

 a distinct membrane, very thin and smooth but suddenly, after a 

 few seconds of observation, the membrane happens to burst, and 

 through the opening expands a voluminous mass of mucilaginous 

 material, mingled with a number of extraordinarily fine dust-like 

 particles (Plate VIII, fig. 67). These globules, in fact, must be 

 considered as quite a special form of trichocysts, the "Schleim- 

 trichocysten" of German authors. But during all the time that 

 the gradual compression of the anunalcule is continued, there are 

 seen to take place inside the compressed plasma small commo- 

 tions, sudden disturbances of equilibrium, explanation of which 

 is difficult to determine; but if India ink is used, the most external 

 of the spherules, which are easily examined singly, are seen to eject 

 a little white cloud when bursting, at the same time that a slight 

 commotion is noticed in the adjacent lining ectoplasm; all these 

 successive commotions that we saw occurring inside the animalcule 

 must then also have their cause in exploding internal trichocysts. 



India ink experiments enable us to observe still more curious 

 phenomena: if the black current is made to touch an animalcule 

 which is in perfect health, and is moving freely under the cover 

 glass, the organism is seen to throw out here and there, now back- 

 wards, now forwards, or on one side, these same wh te little clouds 

 which we observed before, and at each of these characteristic ex- 

 plosions, the animalcule leaps backward or forward or to one side. 

 It is, indeed, a very interesting thing to follow one of these little 

 animals while swimming at full speed, discharging without inter- 

 mission its projectiles, like a man-of-war that would bombard the 



