these genera, which appeared earlier geologically than our coram 

 Echinus (Fig. 103, Strongylocentrotus Drobachiensis), are lower 



Development of the Holotlmroids. Of the development of 



native sea cucumbers our knowledge is exceedingly fragments 

 and for nearly all that we do know of the mode of gro 

 of these animals in general, we are indebted to the els 



