I/ jriaas.tar ooraceus presents Uu three follo^in^ well 

 marked physiologic*! spates (1) "Rigid" (L) "loconiotor" (3) 

 "active but unorientod* i'he responses of th-i tutu feet, and 

 arms differ markedly according to tha physiological state of 

 the animal Other starfish studied present analogous states* 



2/ intension of t ,e tuba feet depends upon the proper 

 physiological st^te and absence o< stimuli which cause Detraction. 



An isolated tuba foot, infl-itod -*ith watar und ir pressure can 



/ 



b3 caused to glonrly oxtend ; but not rjuite normally, 



r? 



3/ At^ching is condition-^ by the proper uTysiolo?ioal 



state. An isolatyl tu :>B foot, properly prap^rud and i 

 with vfat^ 1 " is rnora apt to a -taoh if taken frota i ri^id starfish 

 than from a loooiaotor stirfisn. Attaching may involve only a 

 part of the ainbulaoral digk. 



4/ .Uth'lr?nral A is a response to cont-iot stimulation, as is 

 dotaohing, under certain oon^ itions 



I/ Th step '-eflex intargrades ^ith the withdrawal response 

 as elicited by 10 ivict stimulation of the ambulacral disk* It 

 is da ;'md3nt upon tirs contact stimulation uvl .t.^e presence of 



the locoiootor irapulsefc vhioh orients the ?tep reflex and conditions 







the tube foot to b-3 rigid and support animal during loootnotion* 

 The tu>>e foot is attached most strongly during the first part of 

 the step raflox* The tube foot is a tachad *ivh 2.8 (A.g farina.) 

 or ii,06 (ryono podia) times as much force as it exerts in pulling 

 against resistance* ITii^ facto/I- is relatively constant for vrious 

 values of the resistance. 'm& strorvjth of the step reflex 



varies markedly with diff3;r3nt spscias* 



/Joordin-tion of thj 'tuDa fjet of ti;e rigid starfish, like 



tint of tha gills, is u siiaple apreid of exuension or rat^ction. 

 It ia ref rabla hypo the tioally to a simple rwrv3 rut. 



