PLATE IX. 

 NERVE FIBRES AND NERVE CELL WITH SPIRAL FIBRE. 



Fig. 1. 



Development of young dark-bordered uerve fibres at a very early period, showing bioplasm and 



iorraed" material of young elementary parts and the fine fibre coiliug spirally round the developing 



dark bordered fibre. X about 1800. 



iineu ner.e fibres vrith their bioplasts ramifX-iv* over an elementary muscular fibre of the white 

 mouse, a a, a, Ca; illa:y vessel. X 1800. 



Astern of hyla or green tree frog. Straight fibre coming from the 

 body of the cell. Spiral fibre, from its circumference The two fibres pursue 

 opposite directions, x 700. 



f an inch 



x 700. 



[To face page 230. 



