FIG. 1 19. Electric organ of the Skate. The left-hand drawing (I) represents the 

 entire organ (natural size) of a fuli-grown /?. radiata. This is a small skate, which 

 rarely exceeds 50 centms. in length ; but in the large R. balis, the organ may 

 exceed two feet in length. The other drawings represent single muscle-fibres in suc- 

 cessive stages of transition. In the first of the series (II) the motor plate, and the nerves 

 connected with it, have already been considerably enlarged. In the other three specimens, 

 the fibre becomes more and more club-like, and eventually cup-like. These changes 

 of shape are expressive of great changes of structure, as may be seen in the last 



of the series (V), where the shallow 



plate lines the concavity of the cup, and is richly si 

 which are represented in the last drawing) : the thic 

 muscular fibres, the striation of which is distinctly visi 



b 



is seen in partial section. The electric 

 supplied with nerves (only a few of 

 ' -k walls of the cup are composed of 

 'ble. 



