NEBELA COLLAEIS. 97 



their heads and displaying their cilia, and, when 

 alarmed, retiring suddenly into the cavity. Whilst 

 this took place the posterior part of the rotifer (it did 

 not exhibit the usual tail-like process) remained sta- 

 tionary for a time ; the anterior half would again 

 slowly extend ; and the ciliated processes would un- 

 fold but a short distance beyond the orifice of the 

 test. The action of the maxillas was distinctly visible 

 through the transparent test-walls. The cilia were 

 used for purposes of locomotion, and it was curious to 

 see a test of Nebela collaris dragged about by the 

 rotifer in its tortuous course through the water. 



FIG. 86. Test of Nebela collaris taken possession of by a rotifer. The 

 maxillae are seen ^ in. (5 mm.) above the aperture of the test. 

 (Ee-drawn from a rough sketch by Mr. Cash.) x 280. 



One example met with was interesting from the 

 fact that the test of the Nebela contained not only a 

 living rotifer apparently young but also, along 

 with it, two ova. The mature rotifer was free, and 

 appeared to make great efforts to escape from its 

 prison, but this was impossible from the fact that the 

 neck was choked with mucus, probably what remained 

 of the rhizopod protoplasm ; and the explanation 

 which suggested itself was that the eggs of the rotifer 

 had been deposited, and were being hatched out, in the 

 cavity of the test. If that were so one is almost 



VOL. n. 7 



