76 THOUGHTS ON ANIMALCULES. 



graphically described by Baker in the following ex- 

 tract : 



" If the water standing in lead gutters, or the slimy sediment it leaves 

 behind, has anything of a reddish colour, one may almost be certain of 

 finding the wheel-animals therein ; and if, in summer, when all the water 

 is dried up. and nothing but dust remains, that dust appears red, or of a 

 dark brown, one shall seldom fail, on putting it in water, to disclose multi- 

 tudes of minute reddish globules, which are, indeed, the animals them- 

 selves, and which will soon change their appearance ; for in the space of 

 half an hour a languid motion begins, the globule turns itself about, 

 lengthens by slow degrees, and becomes in the form of a transparent ca- 

 terpillar ; and appears lengthening out its body considerably at some 

 times, and contracting it as much at others. Its motion from place to 

 place is likewise then performed in the manner of such creatures : fixing 

 first its tail, and extending its whole body ; then fastening its head, and 

 drawing up its tail to it, (see pi. xn, fig. 6) ; and so on, by which it gets 

 along pretty nimbly. But one shall often behold it changing this ap- 

 pearance in an instant, and assuming a form extremely different ; for its 

 snout being pulled somewhat inward, the front end becomes clubbed, and 

 immediately dividing, exhibits most surprisingly to view a couple of semi- 

 circular instruments before unseen, round the edges whereof many little 

 fibrilltB (cilia) move themselves very briskly ; sometimes with a kind of 

 rotation, and sometimes in a vibrating or trembling manner. An opening 

 or mouth also appears in the middle between these two semicircles. 

 When in this condition the animal is often seen to unfasten its tail, and 

 swim along with a great deal of swiftness, seemingly in pursuit of prey. 

 When the fore part of the creature first appears to open or divide, the in- 

 struments above described, which, when fully protruded, resemble a pair 

 of wheels having a quick rotation, coming then but a little way beyond 

 their tubular cases, and being in that condition like round pieces of paper 

 folded in the middle, or funnels whose sides are flattened almost together, 

 seem only like a couple of semicircular parts, about the edges whereof 

 what are seen afterwards like the teeth of wheels appear only as little 



