OF ANIMALCULES. lOJ 



more transparent^ which indicates that the animalcule is 

 about to divide. The tail in this species is merely a gra- 

 dual diminution of the body : Muller has shewn it as 

 being forked, but I have not detected any division, al- 

 though I have examined it under very excellent magni- 

 fiers : it is probably an optical illusion, caused by its 

 vibration. The body is very flexible, and capable of con- 

 tracting into a globular mass, as shewn in figure 106. 

 In this form it revolves in the water, and is about 1 -1000th 

 of an inch in diameter, and might be easily mistaken for 

 a species of the Volvox, some of which are generally 

 found in the same drop of water, especially the orange- 

 coloured, which are about the same size ; as also the 

 Monas puMsculus, and the green spindle animalcule, 

 (Astasia euchhra, E.) Sometimes it withdraws its tail, as 

 shewn at figure 109, and often swims about in a slow 

 and graceful manner, with only its body contracted, as 

 shewn at figure 105. In all their forms, except the glo- 

 bular, which they invariably assume when the water 

 has nearly evaporated, these animalcules are very rest- 

 less, swimming about near the edges of the water. 



Whether the alimentary structure of this animalcule 

 is polygastric has not been demonstrated, from the difii- 

 culty there is to make it take coloured food ; which re- 

 mark is applicable to all animalcules of this colour. It 

 propagates by division, and from the minuteness of some 

 of the young, compared with the larger ones, it is pro - 

 bable they are also produced from ova. 



It may be useful to mention, that If by accident they 



