ELEMENTS OF HISTOLOGY. 



[Chap. V. 



processes ; and intermediate forms between the two. 

 But on careful examination it will be seen that these 



B 



Fig. 27. Pigment Cells of the Tail of Tadpole. 



A, B, c, D represent various states ; A being a cell in an uncontracted or passive 

 state, D in a contracted or active state. 



appearances are due to different states of contraction 

 of the same kind of cells (Fig. 27). 



43. In the lower vertebrates the dark pigment 

 cells show marked contractility, inasmuch as they are 

 capable of altogether withdrawing into their body the 

 pigmented processes. In the passive state these are 



