15 



CHAPTEK II. 



THE HISTORY OF THE LITERATURE CONCERNING THE 



ROTIFER A. 



IT is nearly 200 years since Mr. JOHN HARRIS, F.E.S., Eector of Winclielsea, pub- 

 lished in the " Philosophical Transactions" } the following " Microscopical Observations" 

 on a drop of some rain water which " had stood in a gallipot in his window" for about 

 two months : 



"I saw here an animal like a large maggot, which could contract itself up into a 

 spherical figure, and then stretch itself out again ; the end of its tail appeared with a 

 forceps like that of an earwig ; I could plainly see it open and shut its mouth, from 

 whence air-bubbles would be frequently discharged. Of them I could number about 

 four or five, and they seemed to be busy with their mouths as if in feeding." 



This description is but vague ; and yet it is very probable that the animal which the 

 rector found in his gallipot was a Rotifer : and if so, this is the earliest notice that we 

 have of the class. 



A few years later, in 1703, LEUWENHOEK published, in the same "Transactions," 2 

 an account of some animalcules, living in sheaths, that he had found at Delft, on green 

 weed brought by the flooding of the Maes from Delft Haven. These little creatures were 

 almost certainly Limnias ceratophylli. Leuwenhoek gives figures of one, and notices 

 its bearing " two wheels thick set with teeth as the wheel of a watch." In a later paper 3 

 in the " Philosophical Transactions" he gives a much better account of Limnias, with 

 greatly improved figures. He states that when the two wheels are viewed frontally they 

 are seen to be continuous and to form but one ; and he adds a figure (PI. B, 4) of the 

 corona so seen, and notices that the ciliary waves run right round the whole wreath 

 in the same direction. 



Leuwenhoek next describes an animal " that has a receptacle or little house com- 

 posed of round bubbles," and furnished with " surprising wheelwork " of four parts, three 

 of which only were shown in his figure, " the fourth being almost hid from sight." One 

 glance at the figure of the animal (PL B, 1), and at its corona (PL B, 2), shows us that 

 he has had Melicerta ringcns under his microscope. 



His next paper 4 on the same Eotiferon is pleasant reading ; for it vividly recalls the 

 shock of delighted surprise with which every naturalist first enters into the enchanted 

 world beneath the waters. 



" I took notice," he says, " of the surprising figure of an animalculum, fixed in a little 

 scabbard or sheath, fastened to some of the small green weeds found in ditches of water. 

 And, as often as I viewed these animalcula and showed them to others,' we could not 

 satisfy ourselves with looking on such surprising objects ; and the more because we 

 could not conceive how so strange a motion, as they all had, could be performed ; as 

 also what should be the use of such a motion." Leuwenhoek also relates how Meli- 

 certa makes its tube pellet by pellet ; and this is his account of it. "I viewed one of 

 these animalcula a good while together ; and observed, several times, one after another, 

 that when the animalculum thrusts its body out of the sheath or case, and that the 



1 Phil. Trans, vol. xix. 1696. 2 Phil. Trans. No. 283, 1703. 



3 Phil. Trans. No. 295, 1705. 4 Phil Trans. No. 337, vol. xxviii. 1713. 



