I02 EDWARD POTTS : 



subject as a victim where before he has been a victor in many 

 combats. Desiring to supply nourishment to a tricapitate 

 form, I injected into his jar some slimy deposit from a piece 

 of board floating on my lily pond, and was rewarded almost 

 immediately by seeing that two of the capitnlo! had each cap- 

 tured a Rotifer vulgaris. The third branch seemed indifferent 

 about food ; perhaps it was sufficiently nourished through a 

 common digestive tract uniting the whole. While the feast 

 of rotifers was going on, a swarm of their late companions, 

 introduced with them into this new locality, crowded around 

 the Microhydra, darkening its middle portions, to taste of the 

 predigested food that there adhered. These proved to be an 

 undetermined species of Trachelomonas, that, though intrud- 

 ers, were not dangerous. Then a third rotifer was so impru- 

 dent as to allow himself to be trapped by the third capitnlum 

 and held. Another " Richmond " now " appeared upon the 

 field," a dozen — fifty or more, crowded around the helpless 

 rotifer like so many ravening wolves or hyenas, from whom, 

 if he had been himself free, he could have easily escaped. 

 The fierce determination of these, and their barrel-like mark- 

 ings, left no doubt in the minds of the obsen^ers that thej- 

 were Coleps hirius (?), the only protozoan I know, so vindict- 

 ively personal in its attacks, which evidently express, "We 

 have come to devour you, and to do it now." Well, they 

 quickly reduced* the rotifer to a ma,ss of pulp, and began 

 upon his late captor, who was as powerless to resist them as 

 the other had been. One, two, three heads succumbed and 

 soon lost their characteristic outlines, when I felt called upon 

 to lend a hand to my friends. I first scattered them by a few 

 puffs from a ball pipette ; but seeing them again gathering to 

 continue their feast I began a war of extermination which, I 

 am happy to say, was more effective than that which has been 

 waged by this community against the English sparrows. 

 Wherever a trace was seen of the material in which they were 

 introduced, it was drawn up and discharged : and I have not 

 seen a Coleps since. I am pleased to be able to state that 



