r6tifers. 231 



The body is flexible, yet the skin is hardened and bears 

 several conspicuous curved spines, two of which are 

 on the sides — one on each — and pointing forward. 

 The foot bears two tail-like spurs, which are shown in 

 the figure projecting beyond the body. The Rotifer 

 is peculiar, and not uncommon. I have found it in 

 summer, and have taken it from under the ice in Feb- 

 ruary. Its color is usually some shade of brown. 



10. Rotifer vulgaris (Fig. 163). 



This is the commonest of'all the Rotifers. Hardly a 

 drop of water from the proper localities comes to the 

 rriicroscope-stage without bringing withit one or more 

 of this abundant and cosmopolitan species. 

 It is usually one of the first animals to at- 

 tract the attention of the microscopist at 

 his earliest attempt to investigate the life 

 within the nearest pond or ditch, and to the 

 end remains almost a constant companion. 



The white body is long, spindle-shaped, 

 and tapers from near the middle to both 

 extremities where the two anterior ciliary 

 disks are unfolded. Ever since the animal 

 was described by Ehrenberg in 1838, until 

 within a few years past, it has been des-' 

 cribed as having only two' toes, whereas it 

 has three; they are small but distinctly L,.' '^^ „, 



' ■' . ,■ Fig. 163.— R6- 



tbree in niamber. This is one of the ' t'fer. 

 many statements of microscopical observations which 

 have been accepted as correct on the dictiim of some' 

 acknowledged authority, who worked many years ago 



