16 GENERAL HISTOET OF 



Uncini arc curved hook-like processes, like thick short hair?. 

 They emanate from the imcler siirface of the body, and in office 

 resemble the feet of larger animals. These organs do not vibrate, 

 have neither bulb nor articulation, but sometimes possess considerable 

 latitude of motion, not serving however for locomotion, but only for 

 prehension. 



Tarialle processes are another description of external members, 

 which perform the function of locomotion ia a very complete manner. 

 In the family Amoehaea, the animalcule appears to have the power 

 of protruding, at pleasure, any portion of its body, to form these 

 processes; a property which has not inaptly obtained for it the 

 designation of protean. In the loricated family Ai'cclKna, the variable 

 processes are definite, the protrusion being restricted to those parts of 

 the body which are situated about the opening in the shell, designed 

 for that purpose. These processes, like the protean ones, are soft or 

 membranous, and resemble, though on a email scale, those of the 

 Mollusca, of which the horns of the common snail are a familiar 

 example. The Infusoria, however, have a greater command than the 

 snails, &c., over these processes, and a more extended action, in pro- 

 portion to their size. 



In the Infusoria of higher organization, such as the Rotatoria, 

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

 are mainly used as organs of attachment. ,Thesc are generally at 

 the extremity of a certain prolongation of the body, which may be 

 designated a foot-like member. To the inexperienced observer, this 

 process has generally been supposed to be the tail ; but, not being 

 placed dorsaUy, with respect to the discharging orifice, it must be 

 considered as occupjTng the position of the foot. In these creatures, 

 there is a large development also of those parts of the body to which 

 the rotatory organs are attached ; and, in the case were two only of 

 these organs are seen, a projection may be noticed on each side of the 

 anterior portion of the animalcule, which has been termed an eur : 

 For example, sec Jig. 41 G. 



Other appendages of Rotatoria, imconnectcd with locomotion, are 

 Horns fCorniculaJ Cirrhi and spines fCalcares.J The first occur as 

 elongated, fleshy, and rather firm projecting points, covering either 

 the entire body, as in Philodina aculcata, or only some portion of it, 



