N. E. GREEN ON CILIARY ACTION IN ROTIFERA. 75 



crest from which the anterior fringe proceeds, and is chiefly instru- 

 mental in taking up particles drawn in by the front series, and 

 conveying them to the mouth, while in Melicerta the second series 

 is placed on the back of the lobes, and the waving movement, in- 

 stead of being in one direction only, as in the outer fringe, is in 

 two directions, both leading to the gullet. 



In all these instances we have been speaking of a movement 

 which, however bewildering, is still distinctly visible ; but there is 

 one member of this family in which the means by which the food 

 is induced to come in, is invisible, at least to any but a most close 

 and patient observer ; we allude to the floscule. How often have 

 we been surprised to see a monad swimming in all the unconscious- 

 ness of animalcule life, in the neighbourhood of one of these crea- 

 tures, taken as it were with a temporary fit of insanity, and pre- 

 cipitate itself into the bell-like mouth, when a slight contraction of 

 the neck indicated that it was all over with the unhappy monad. 

 Surprised we have been indeed, and sorely puzzled to divine the 

 cause of these strange movements, or to make out the hidden 

 source of their power. 



Slack, in his charming work, " Marvels of Pond Life," page 76, 

 refers to this power in these words : " Some internal ciliary action, 

 quite distinct from the hairs, and which has never been precisely 

 understood, caused gentle currents to flow towards the mouth in 

 the middle of the lobes," &c. ; and in Prichard's standard work, 

 page 667, Gosse is quoted as an authority : " That in Floscularia 

 rotation is accomplished not by the tufts of long setas, but by cilia 

 set, on the inner surface of the disc." This seems very definite, 

 but we read again, page 675, with the authority of the same name, 

 " That the setigerous lobes are not the true rotatory organ, yet 

 there is a rotatory organ, the particles of floating matter revolving 

 in a perpendicular oval within the mouth of the disc, hence I con- 

 clude that the rotatory cilia are set in the inner surface of the 

 disc." 



We find from these quotations that both Slack and Gosse have 

 regarded the precise situation and nature of the rotatory organ of 

 the floscule as still open to investigation. Having been supplied by 

 our good friend, Mr. George Fryer, with a stock of these in- 

 teresting creatures from his tank, we set to work to unravel the 

 mystery ; but many means, and kinds of illumination were tried 

 without avail. There lay the beautiful floscule, apparently motion- 



