76 N. E. GREEN ON CILIARY ACTION IN ROTIFERA. 



less, yet the mad gallop of the monads continued, some driving 

 backwards and forwards before the opening to the mouth, but 

 meeting on every side an almost impenetrable series of setae, were 

 at last compelled to enter ; here we have seen three or four at a 

 time awaiting their fate, when presently the ominous contraction of 

 the neck is given, a beak-like process advances from the centre, and 

 with unerring aim seizes on each in succession. Most provoking, 

 certainly, and not to know anything about it. So, to work again, 

 this time trying dark ground illumination with T ^, and by this 

 means much was learned of the quiverings, shudderings, or strikings 

 of the seta3 ; these movements were sometimes so continuous and 

 effective that both Mr. Fryer and the writer thought that the seat 

 of power lay in the shorter spurs of seta?, which extend far into 

 the bell-like opening ; but a more prolonged examination made it 

 evident that these movements were employed rather to keep the 

 passage clear, or to increase the current, than to form the current 

 itself, for this still continued when the seta? were at rest. 



At last, having given them a few days to consider whether they 

 would yield their secret or no, we commenced operations one even- 

 ing about eight, on a specimen extended bell-upwards, and working 

 so slowly that some particles of indigo with which it had been 

 regaled on a previous occasion, were flowing slowly over the brim 

 into the cup, and coming out again at an equally steady rate. The 

 resolve was immediately made to trace the course of these particles, 

 being assured that wherever the hidden cilia might be, there the 

 movement of the indigo would be most accelerated or disturbed. 

 Many particles were watched in succession ; they passed unmoved 

 over the shorter seta?, where, on other occasions, we had seen them 

 driven about in wild confusion ; but on arriving at the contraction 

 of the neck, and just at that j3art where the interior bulges out into 

 a wider form, they were invariably agitated, some passing over it 

 with a jerk, while others were returned in their course, thus com- 

 pleting the perpendicular oval referred to by Gosse. Those particles 

 which had passed this rim were observed to cross leisurely over the 

 flattened surface which surrounds the mouth ; but in coming out 

 were again disturbed or jerked, some, indeed, were retained and 

 agitated in such a manner that an imaginative eye might readily 

 have seen the cilia by which their dance was produced ; but being 

 in a very matter-of-fact mood, we only felt assured that there they 

 were, if we could only see them. Still, after some hours of effort, 



