On (Eeistes umhella and other Rotifers. By C. T. Hudson. 5 



piece of the weed, in whicli several specimens of both creatures 

 were entangled, under the Microscope, and with a low power 

 watched eagerly to see if I could catch the rotifer in the fact. 

 After a few minutes' observation, I was inclined to reject the idea as 

 absurd. 



The Yorticellae rushed backwards and forwards, knocked fear- 

 lessly against the rotifers, and, while evidently frightening the 

 latter, took no sort of pains to get out of their way ; in fact, 

 behaved, as to me they always do seem to behave, just like animated 

 machines. As to the slow-swimming and still slower crawling 

 rotifer catching one of these swift rovers, the thing seemed impossible. 

 Under any circumstances, whether swimming or crawling, whenever 

 the Vorticella struck the Notommata, the latter either drew in his 

 wheels, and ignominiously rolled over and over to the bottom, or if 

 it were crawling on a bit of the weed it shrunk back, and contracted 

 itself with every appearance of alarm. 



Still there were two ugly facts unaccounted for, viz. the dis- 

 appearance of the Vorticellae, and the appearance in the stomachs 

 of the Notommata of substance marvellously like them. I was just 

 going to try to imprison a Notommata in a coil of cotton with one 

 or two of the Yorticellae, when I noticed one of the latter caught in 

 the angle between two small stems of horn-wort. A Notommata, 

 too, was crawling along one of the stems in its usual slow fashion. 

 There was a chance that the sluggish creeper might get to the 

 angle before the Vorticella darted off again on its travels. For- 

 tune favoured me ; the Vorticella kept waltzing round and round 

 in the same spot, and the Notommata crawled on till it all but 

 touched the Vorticella. I hoped to see the rotifer quicken its 

 pace, or make — I will not say a dart, that would be too much, 

 but at all events a lurch at its prey ; imagine my chagrin when 

 I saw it coolly curl round the stem and begin to retrace its steps, 

 actually freeing the Vorticella from its prison by brushing it with its 

 back as it crawled back again. There had not been a thousandth of 

 an inch separating the rotifer s head from the Vorticella, and yet, 

 in spite of its two eyes, it had not noticed it. Again, I thought of 

 bringing in a verdict of " not guilty " ; but another good look at 

 dark green stomachs revived all my suspicions, and once more 1 

 patiently waited till another Vorticella, possibly the same, re- 

 peated its silly performance of getting into a corner and dancing 

 there till some one should set it free. This time it was freed only 

 too effectually. The Notommata once more crawled down to the 

 captive, " without hurry or care," and struck its nose (if I may 

 use the expression) against the Vorticella, just as if it were by 

 accident. But the instant it did so it jerked up its head, and 

 snapped at and seized its victim with its sharp jaws ; and in a 

 second I saw the whole contents of the Vorticella pouring down 



