PLATE I 

 The Light-sensitive Apparatus of the Starfish 



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Fitt. 1. — Maiih<istcrliis (/Idruilis, showing th(> ]>nsiti()ii of the eye-spot, e.s. 

 one of which is jjresent at the tip of each of the five arms. 



Fig. 2. — The excised eye-spot (optic cushion) showing the 

 o])tic cups, o.c. They have a striking red colom- due to 

 L'-carotene and esterified astaxanthin; it is to be noted 

 that some of the colour of the body-wall, which is also 

 light-sensitive, is due to the same ])igments (X. ]\Iillott, 

 Endeavour, 1957). 



S.O. — VOL.1 



[To face 2>- 186. 



