136 



DESCRIPTION OF PLATE XII. 



ROTIFERS, OR WHEEL-ANIMALCULES. 

 ( PAGE 71. ) 



FIG. 1. The Pitcher- shaped Brachionus, (B. urceolaris) ; p. 79. 



a, The jaws. 



b, The carapace, or shell. 

 e, The pair of rotators. 



d, The pedicle, or tail. 



e, e, Ova, or eggs, attached to the body of the animalcule. 

 FIG. la. The jaws and teeth of fig. 1, highly magnified. 



FIG. 2. Baker's Brachionus, (B. Bakeri} ; p. 89 ; the letters have the 



same references as above. 



FIG. 2a. The jaws and teeth of Baker's Brachionus. 

 FIG. 3. The Common Wheel-animalcule, (Rotifer vulgaris) ; reduced 



from Ehrenberg's figure ; p. 73. 



a, The trunk or proboscis, on which the two red eyes air 

 placed. 



b, b, The rotators, or wheels. The course of the eddies in- 



duced by the cilia is denoted by the arrows. 



c, The respiratory tube. 



d, The masticatory apparatus, or jaws and teeth. 



e, e, The alimentary canal coloured by carmine. The direc- 

 tion of the currents occasioned by the vibration of the cilia 

 of the mouth is shewn by the coloured arrows. 



