PLATE LXXIII. 



FIG. i. Pycnopodia helianthoides. Young, with sixteen rays, showing regular 

 normal mode of interpolation of new rays ; I, odd anterior primary 

 ray; 2, 3, 4, 5, 6, successive pairs of interpolated rays; a, odd 

 posterior primary ray; b, b' and c, c' second and third pairs of 

 primary posterior rays ; X 2. 



FIG. 2. Leptasterias inequalis Verrill. Type. Dorsal side; a, ossicles, with 

 spines removed ; X 2. 



(148) 



