180 WHEEL-BEARING ANIMALCULES. 



will to stationary objects: in some, these pincers 

 terminate a long muscular tail-like appendage; but 

 in others, the pincers terminate a 

 mere projection. The mouth leads 

 into a gullet, which varies remark- 

 ably in size in different species : in 

 some it is very capacious ; but in 

 others it is a narrow canal. The 

 gullet leads to a gizzard, or pre- 

 PINCEHS or AN paratory receptacle, in which, by 

 LE ' means of a curious apparatus, the 

 food is either ground to pulp, or cut into fragments. 

 This apparatus is described by Ehrenberg as 

 consisting of three teeth, 

 which, by the action of the 

 gizzard and of certain muscles 

 belonging to them, work 

 vigorously on each other, and 

 so mince to pieces whatever 

 is subjected to their operation. 

 GIZZARD OF AN ANIMAL- These teeth are three in num- 

 ber, as in the sketch, and 



consist of one central and two lateral or superior 

 ones : the central tooth is apparently fixed, and has 

 two flattened facets on its upper surface, one for 

 each superior tooth to work upon. Each of these 

 superior teeth consists of two portions, namely, a 

 basal portion, fixed to the walls of the gizzard, and 

 serving for the attachment of muscular fibres ; and 

 a free movable portion, which may be regarded as 



