THE FROG : HISTOLOGY, GERM CELLS, DEATH 95 



Muscular 

 Tissues. 



the other a process which has the structure of a fibre but 

 functions as a dendrite, bringing in impulses from sense cells. 

 Muscular tissue consists of elongated elements, either 

 cells or coenocytes, known as fibres, in which 

 the power of contraction is highly developed. 

 It is of two kinds, striped or striated, and plain, 

 unstriped or unstri- , 



ated. Involuntary 

 muscle (see p. 40) 

 is generally un- 

 striped, voluntary 

 muscle striped. 

 The fibres of plain 



Fig. 54. — Diagram of part of 

 a neuron highly magnified. 



ax., Axon; c.b., cell body; d., 

 dendrites ; »«., nucleus. 



containing many nuclei. 



muscle are cells of an elongated 

 spindle shape with a single 

 ©val nucleus in the middle. 

 They show a faint longitudinal 

 striation, have each a delicate 

 sheath, and when they occur 

 in masses are joined by a little 

 intercellular cement substance, 

 across which threads of proto- 

 plasm keep them in continuity 

 (Fig. 5). )(The fibres of striped 

 muscle are larger than those of 

 plain muscle, and can be seen 

 with the naked eye if a portion 

 of one of the great voluntary 

 muscles be teased into frag- 

 ments. Each is a ccenocyte, 

 The fibre is cylindrical, tapering 



at the ends, It is covered by a transparent elastic 



