18 GENERAL HISTORY OF 



subulate ; others have a knob at the extremity, and hence 

 termed capitate. 



Styles are thick straight setae, usually seated on the 

 under side of the body, posteriorly, and resembling the 

 tail feathers of birds. These never vibrate ; neither have 

 they a bulbous base, nor are their extremities bent or 

 hooked. They are used for the support of the body, and 

 for climbing. 



Uncini are curved hook-like processes, like thick short 

 hairs. They emanate from the under surface of the body, 

 and resemble the feet of larger animals. These organs do 

 not vibrate, have neither bulb nor articulation, but some- 

 times possess considerable latitude of motion. 



Variable processes are another description of external 

 members, which perform the function of locomotion in a 

 very complete manner. In the family Amoebaea, the 

 animalcule appears to have the power of protruding, at 

 pleasure, any portion of its body, to form these processes ; 

 a qualification which has not inaptly obtained for it the 

 designation of protean. In the loricated family Arcellina, 

 the variable processes are definite, the protrusion being 

 restricted to those parts of the body which are situated 

 near the opening in the shell, designed for that purpose. 

 These processes, like the protean ones, are soft or mem- 

 braneous, and resemble, though on a small scale, those of 

 the Molusca, of which the horns of the common snail are 

 a familiar example. The Infusoria, however, have a greater 

 command than the snails, &c. have over these processes, 

 and a more extended action, in proportion to their size. 



In the Infusoria of higher organization, such as the 

 Rotatoria, there are definite processes, of a toe or claw-like 



