STRUCTURAL CHARACTERS OF ANIMAL ORGANISMS. 43 



higher animals. Muscle tissue is, almost invariably, connected 

 FIG. 22. 



FIG. 22. Cells of smooth muscle tissue from the intestinal tract of rabbit. 

 (Ranvier.) A and B. Muscle cells in which differentiation of the proto- 

 plasm can be well seen. (Schiifer.) 



FIG. 23. Two fibres of striated muscle, in which the contractile substance 

 (MI) has been ruptured and separated from the sarcolemma (a) and (s) ; (p) 

 space under sarcolemma. (Ranvier.) 



with nerve tissue, and acts in response to stimuli communicated 



