ON THE HAUNTS AND HABITS OP THE ROTIFERA. 87 



tremula, are very different. The former is the swiftest and most restless of the Eotifera ; 

 it is the very swallow of the waters, ever whirling round and round in endless spirals, 

 and never still for a single instant from its birth till its death ; but the latter may be 

 constantly seen drifting along in some gentle current, while twisting round at the end of 

 a long thread spun from its toes, and fastened to some floating object. 



Of course, creatures with habits like these can be captured only by making random 

 dips in the water, now at the surface, now deeper down — here in the sunshine, and there 

 in the shade ; for even Eotifera have their fancies, and are sometimes swarming in one 

 particular spot, while all the rest of the pond is deserted by them. 



I have, however, noticed that they specially affect the neighbourhood of a forest of 

 weeds growing up from the bottom ; waltzing up and down outside of them in myriads, 

 like gnats under the trees in summer. 



There is yet another free swimmer that avoids the shore, and sails out into the open 

 sea ; viz. Anuraa loncjispina. This curious creature has a lorica like a Greenlander's 

 canoe, or a University eight, and it keeps off from the weeds and algre, as if fearing lest 

 it should be entangled for life if it once got among them. It was discovered by Professor 

 D. S. Kellicott in Niagara water at Buffalo, U.S., in 1879, and was found almost imme- 

 diately afterwards in the Olton Reservoir, near Birmingham and since then in Lake 

 Zug in Switzerland. It appears to be a rare species, though its rarity may bo due 

 partly to the fact that it often requires a boat to catch it; and an ordinary Rotifer hunter 

 can hardly be expected to add this to his apparatus. 



The known habitats of the Pedalionida: are at present very few. I had the good 

 fortune to be the first to light on Pedalion mirum. It was in July 1871 that I found 

 it in a small roadside pool at the top of Nightingale Valley, close to Clifton. Soon 

 afterwards I dipped it from a fine old pond at Abbot's Leigh, about two miles distant from 

 Nightingale Valley. It reappeared in this pond in the following year, but since then it 

 has not revisited the neighbourhood. It has been met with several times near Chester 

 and Birmingham, and on one occasion it was tolerably abundant in the warm water-lily 

 tank in the Duke of Westminster's gardens at Eaton. 1 



Dr. L. K, Schmarda discovered in Egypt, in 1853, in some brackish pools near 

 El-Kab, a sis-limbed Rotiferon, Hexarthra polyptera, which evidently belongs to the 

 same family, though it must be placed in a different genus. He says that there were 

 great swarms of them distinctly visible to the naked eye, in a pool of very transparent, 

 colourless water, of a strong brackish taste. 



Now, a Rotiferon that is equally at home in dirty puddles, clear ponds, warm-water 

 tanks, and brackish pools, ought not to be a rare one : and yet Pedalion is rare. 



Possibly its apparent rarity is due to its being constantly mistaken for an Entomo- 

 stracous larva. I was on the point of throwing the water away, when I first 

 dipped Pedalion out of the pool in Nightingale Valley. Its skipping movement is so 

 precisely that of the young of a Cyclops, that I thought I had caught nothing more 

 valuable than these ever-present nuisances. Fortunately I noticed that, unlike them, 

 my captives seemed to glide along after every skip, instead of stopping stock-still to 

 gather breath for a fresh jump ; and so, thinking that they might possibly be some large 

 sort of Polyarthra, took them home for further investigation. But it is very probable 

 that Pedalion has been thrown away hundreds of times, and will be so again, as this 

 happened to me after nearly twenty years' experience in catching Rotifera.' 2 



Rotifera may often be seen perched just under the plumed heads of one of the fresh - 



1 M. J. Barrois described, in the licvue Scicntifique, No. 13, 1877, p. 303, a marine Rotiferon under 

 the name Pedalion, and gave an account of its embryology. His description, however, shows that the 

 animal was of the genus Synchceta. 



2 It is a pity that Pedalion is not more frequently met with, as there are some points in its structure 

 that yet remain to be cleared up ; and as it is such a striking link between the Rotifera and the 

 Arthropoda. Mr. T. Bolton, of Birmingham, has, however, succeeded in preserving specimens as micro- 

 scopic objects, and they can generally be obtained from him. 



