RHEOTROPISM IN UROSALPINX CINEREA SAY

¹ UNITED STATES BUREAU OF FISHERIES

If Urosalpinx cinerea Say is placed in a current of water it will orient and move against the current. It has been possible to measure the rate of turning and the rate of creeping at various current rates. These results indicate that the rate of turning (degrees deflection per centimeter of path) is a function of the current velocity and that when plotted respectively as effect and intensity the curve obtained follows the usual effect vs. intensity curve obtained for other tropistic reactions. The organs of stimulation for this response seem to be the proprioreceptors in the symmetrical parietal musculature of the animal. Although the rate of creeping is independent of the rate of current, the amount of resistance overcome (or the work done) is also a function of the current velocity.