122 On a Neiv Rotifer. 



in a second, that is to say, at a rate which in a man ■would be 

 upwards of 200 miles an hour. 



Every new rotifer is a new difficulty. Ilijdaiina is troublesome 

 enough, for it is never still, and will not bear compression. Sijn- 

 cliseta has in addition the charming habit of turning over head and 

 heels. Triarthra and its small cousin Polijartlira by help of 

 their spines and plumes add skipping to theu' other accomplish- 

 ments, and were, till I found Peclalion, the most vexatious of all 

 the rotifers. 



But while theTj are chary of using their full powers — reserving 

 them for great occasions, such as when they fall foul of each other 

 or run against the sides of their prison — Peclalion skips habitually 

 without the shghtest provocation, and at tolerably regular intervals, 

 so as to drive an observer into a fit of nervous irritation. 



Now it is hopeless to attempt to make out its shape or internal 

 structure unless the creature can be kept tolerably still, and yet I 

 found it impossible to hit upon any way of ensuring this at my 

 own pleasure. If I secured Pedalion between the two plates of the 

 compressorium, it was only to see its limbs reversed and thrown 

 into unnatural attitudes, hiding often the very things I wanted to 

 look at. If I placed it in a very tiny drop of water and gave it 

 just room to swim in, before many minutes had elapsed it either 

 jerked itself half out of the drop and lay sprawling, helpless, and 

 disfigured ; or with its back adhering to the concave boundary of 

 the water it kept " squirming around " (as a young American lady 

 described it to me) like a horse in a circus. 



It was clear that, unless the rotifer would of its own accord sit 

 for its portrait, there was no Plate to be had for the ' Microscopical 

 Journal,' so I abandoned the heroic methods and tried coaxing and 

 patience. 



I first placed one or two scraps of conferva on the under-glass 

 of the compressorium so as to cross each other, and then I went to 

 my tank in which the rotifers were, and, watching till the currents 

 that are always rising and falling in it, had swept into one corner 

 a tolerably dense crowd of them, I drew up a score or two with a 

 pipette, and dropped them with as little water as possible on the 

 interlacing weed. 



On placing the cover over them, and gently compressing the 

 weed, I had of course many rotifers entrapped in small live cages 

 deep enough for them to swim in pretty freely without getting far 

 out of range. It was a pretty sight to see them darting about, 

 diving, skipping, and rolling in every direction ; but I began to fear 

 that my scheme would fail, for I seemed to have made them more 

 restless than ever. After a while, however, they seemed to get tired, 

 or to be reconciled to their prison, and then one or two settled down 

 to exploring the confervae, saihng along with their mouths and 



