71 



On Ciliary Action in Eotifera. 



By N. E. Green. 



{Read April 22nd, 1870.) 



The subject of ciliary action in Rotifer a cannot but be interest- 

 ing. The movements of these wonderful hairs — which seem to 

 perform not only the duties of hands and feet, but to supply the 

 place of all the five senses combined — are the first to attract atten- 

 tion when looking at this phase of animalcule life as exhibited in 

 the microscope ; and when an earnest examination of the nature of 

 these movements is commenced, the study acquires a fascination 

 peculiarly its own. 



In order somewhat to systematise the treatment of the subject, 

 we propose to divide the general action of cilia into groups, 

 speaking first of those hairs which occupy a forward position, and 

 are thus placed nearest the source of supply. These, for want of 

 a better name, we will call " informers," their apparent duty being 

 to ascertain the state of the surrounding water, and give timely 

 notice of the approach of food. We will, then, offer a few obser- 

 vations on the construction and movements of those wonderful 

 crests of undulating cilia, usually called the wheels, from whose 

 action a continuous supply of nutriment is derived, and brought 

 within reach even of those occupying a fixed position. From these 

 we will pass to a consideration of those cilia which examine, and 

 receive or reject, the various particles drawn in by the action of the 

 wheels, and from this important duty deserve well the title of 

 " inspectors ;" and conclude the paper with a few remarks on the 

 cilia which line the gullet, and whose occupation is evidently to 

 thrust forward the food into contact with the gizzard, or, in the 

 absence of this organ, to make it up in pellets suited for home 

 consumption. 



The cilia which we have called the informers, and whose duty 

 appears to be to convey information of the state of the surrounding 

 water, are few and short in the common rotifer, and long and 



