7- 



i nor eased or decreased by raising or lowering a reservoir, which 

 was connected to the capillary tube by a lon& rubber tube* 

 If the tube feet were injected with water at a pressure of 

 10 cm (HgO) they would slowly extend in the absence of contact 

 stimulation but not to their .vhola normal length* The extension 

 was much slower than the active extension of a norraal tube 

 foot and not so complete. If caused to contract and then 

 injected *ith a pressure of more than 2 ra (HgO) the extension 

 was not appreciably accelerated but could be made more complete* 



Tube feet anaesthetized in Kg SO A would extend completely under 



* 



low pressures. This anaesthetization involved/ also relaxation 

 of the circular muscles so tint the tube foot presented a 

 noticeably greater diameter than the normal tube foot* In the 

 extended as well as the contracted tube feet there was a quite 



constant curvature in the direction of a clear longitudinal 



<3l0n<?11ze side 

 Line up-^hrr-sfet of the pedicel which I take to be the 



pseudohaemal canal (Ouenot 1888) This curvature persists in 

 the anaesthetized (or dead) pedicel and is therefore probably 

 due to mechanical rather than to physiological factors* 



Active tube foot preparations were allowed to extend and 

 assume their normal curvature toward the pseudohaemal canal, 

 and then were bent slowly and gently in some other direction. 

 They showed a tendency to remain bent in that direction and 

 then slowly to bend back to the original curvature* An 



anaesthetized or a dead tube foot does not show this behavior* 



c, 

 It is hense physiological in its nature and is perhaps 



analagous to the behavior of a aea-urohin's spine when bent 

 over to one side/ (Yon Uexkull 1900 ) 



Attaching 



Attaching is conditioned by the physiological state of 



