WHEEL ANIMALCULES 



161 



w.a. 



In some wheel animalcules there is a pair of these 

 spurs, and the very 

 remarkable wheel 

 animalcule drawn in 

 Figs. 35 and 36 has 

 six large processes 

 which, though much 

 bigger, appear to be 

 of the same nature. 

 Of these four are seen 

 in Fig. 35, namely, 

 d.L, the dorsal limb, 

 v.l., the great ventral 

 limb, and 1.1} and /./. 2 , 

 the two lateral limbs 

 of the right side, all 

 of them carrying fan- 

 like groups of fringed 

 hairs. They are moved 

 by very powerful 

 muscles, and strike the 

 water with energetic 

 strokes, so as to cause 

 the little owner to 

 dart through it. This 

 jumping or darting 

 wheel animalcule is 

 called "Pedalion," 

 and was discovered 

 and described by 

 Dr. Hudson. It is 

 so astonishing and 

 wonderful a little 

 beast, that when Dr. 

 Hudson sent me some alive in a tube by post in 1872, 

 11 



Fig. 35. — The Rotifer Pedalion mirum — 

 seen from the right side, magnified 180 

 diameters. w.a., wheel apparatus or 

 "ciliated" margin of the cephalic disc. 

 r.e., right side eye -spot, m., mouth. 

 p., tactile process, d.l., median dorsal 

 limb (as it is seen in profile, only three of 

 the fringed hairs at its extremity are seen). 

 v. /., the great ventral limb (only five of 

 its fan of eight fringed hairs are seen). 

 Z./. 1 , dorso-lateral, and /./. 2 , ventro-lateral 

 limbs of the right side : they show the 

 complete fans .of eight fringed hairs. 

 x., the pair of posterior processes tipped 

 with vibratile cilia, better seen in Fig. 36. 



