ELEMENTS OF HISTOLOGY. 



[Chap V. 



processes ; and intermediate forms between the two. 

 But on careful examination it will be seen that these 



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



A, B, c, D represent various states ; A being a cell in an un contracted 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 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 



