May 1, I860.] 



HARDWICKE'S SCIENCE-GOSSIP. 



U7 



THE WHEEL ANIMALCULE. 



OME years ago I pur- 

 chased an eighteeu- 

 inch propagating 

 glass, and, taking time 

 to think well over and 

 prepare the best ma- 

 terials for furnishing 

 and stocking it (with the parti- 

 culars of which I will not trou- 

 ble you, as I do not think they 

 have any special bearing on the 

 present subject), I eventually 

 set it to work. Eor several 

 years all went on in the usual 

 jogtrot way — weeds over luxu- 

 riant, especially the willow moss 

 (Fontinalis antipyretiea), which 

 successfully quarrelled with all 

 others; snails fat and prolific; 

 and newts as happy as their 

 meditative natures will permit ; 

 add a few common diatoms, 

 entomostraca, and vorticella, and, so far, I think 

 you have all. But I was to receive a better reward 

 for my trouble. One fine April morning, having an 

 hour between breakfast and "bus," I took the 

 shade from the microscope, and, there being no 

 better object at hand, put a scurfy-looking leaf of 

 Anacharis in the live-box under an inch and a half 

 objective, when, to my utter astonishment and un- 

 bounded delight, I counted eight specimens of the 

 Stephenoceros Eich/tornii and three of Floscularia 

 omata — prizes I had tried for in vain for years 

 past. Another and another leaf I examined with 

 ecpial success : the water, or rather the plants, 

 swarmed with them. The hour too soon gone, I 

 left them, but oidy to renew their acquaintance 

 during that and many subsequent evenings. I soon 

 discovered that they were perfect giants of their 

 race. The only published drawings I have seen 

 that did justice to them are those of Mr. P. H. 

 Gosse, in the first two numbers of the Popular Science 

 Review ; the portraits of all others seem to me to 

 have been taken from half-starved or dead speci- 

 No. 53. 



mens, from many of which it is really difficult to 

 recognize the living animals. During the summer 

 and autumn they continued in equal abundance, 

 the Stephenoceros, however, keeping the lead. 

 Almost as suddenly as they came they disappeared, 

 and left behind them, on almost everything in the 

 aquarium, innumerable quantities of their winter 

 eggs, statoblasts. The winter past, indoor residence 

 and spring sunshine warmed these into activity, 

 and, if possible, I think there were more this second 

 than the first season ; but the order of precedence 

 was changed, and the late opposition Eloscularia 

 had it by a large majority. Amongst these now 

 appeared, sparingly, another candidate for favour, 

 the curious little Melicerta ringens, which, to make 

 the story short, the next or third year, drove out 

 with the exception of a solitary individual here and 

 there, the other two. How about the struggle for 

 existence that Mr. Darwin tells us about? It 

 must have been sharp, short, and decisive in this 

 case. 



I have said thus much on these three tube-bear- 

 ing Rotifers, as they were to me the most interest- 

 ing ; but there were several of the free-swimming 

 species in equal abundance and size, and on submit- 

 ting a bottle of the contents of my tank to a gentle- 

 man who had made this class of objects his study, 

 he pointed out several specimens which he called the 

 Yellow Salpa:, but did not give the scientific name, 

 and I omitted to take any notes or drawings of it. 

 It was very like Salpina mucronata as figured in 

 Prichard's " Infusoria," and which he said he had 

 only seen once, and that sparingly, during the pre- 

 vious twelve years. 



But it must not be supposed that wheel animal- 

 cules were the only inhabitants of my aquarium. 

 On referring to my drawings, I find large trees of 

 Vorticellina, of the genus Carehesium, others living 

 in single blessedness, and producing their budding 

 progeny in the most grotesque ways imaginable. 

 There were plenty of well-to-do-looking Stentors, 

 several of the tube animalcules, one fellow especially 

 who was a general favourite (Vaginicola crystallina). 

 Put into a small zoophyte trough, he would expand 



F 



