56 THOUGHTS ON ANIMALCULES. 



jaws of the Rotifer (ligns. 1 and 6) and of the Floscu- 

 laria, (lign. 5, fig.' 1). 



LION. 6. Jaws and Teeth of the ROTJFEB, highly magnified. 



In other species, with the same type of masticatory 

 apparatus, the jaws are furnished with several teeth; 

 as in the Stephanoceros, or Crowned Animalcule, in 

 which there are two distinct sets of teeth on each side, 

 as shewn in the annexed figures. 



7 '2 



LIGN. 7. Jaws and Teeth of the STEPHAKOCEROS, highly magnified. 



Fig. 1. The Upper Set of Teeth, marked a, in fig. 2. 



Fig. 2. The Double Set of Dental Organs, in their natural position. 



Fig. 3, The Lower Set of Teeth, marked b, in fig. 2. 



Respiration, or, more properly, the aeration of the 

 fluids, is effected in the Rotifera by the constant in- 

 troduction of fresh water through one or more aper- 



