108 University of California Publications in Zoology. [Vol. 4 



5. Position Talxcn when tJis Starfish is Confined in a Uni- 

 formly Illuminated Field. — When the starfish is placed in a 

 shallow vessel with strong lieht coming" from one side, so that 



Fig. 9. — Outlines of the position of orientation in two resting starfish. 

 The direction from which the light conies is indicated by the arrows. 



there is no chance to find a dark region, the animal takes a char- 

 acteristic position. If it is resting on a nniform flat snrface, it 

 directs the tips of all the rays away from the lighted side, so that 

 it becomes characteristically of a bilaterally symmetrical form 

 (fig. 9), though of course with some divergences from this form. 



