382 



ROBERT TRACY JACKSON ON ECHINI. 



245 



TEXT-FIGS. 245, 246. Melonechinus muLtiporus. 

 X 2. Adapted from original drawing of Plate 57, fig.l. 



245. Showing typical character of ambulacrum, 

 also ventral developing and dorsal localized stages. 



246. Interambulacrum showing number of rows on 

 the left, and the introduction of columns on the right. 



