254 H - P - KJERSKOG AGERSBORG. 



EXPLANATION TO PLATE I. 



FIGS. 1-3. Photos of Pycnopodia helienthoides (Stimpson), showing righting 

 movements; Fig. i shows the ventral side, and the beginning of righting. Note 

 the outstretching tube-feet; Fig. 2 shows the same specimen ten seconds later, 

 almost semi-righted: Fig. 3 shows the righted specimen, just after righting active y 

 moving along 1 natural size. 



