-67 



bizarre forms, until it had succeeded in getting its ventral 

 side down^when.the squirming cesed, 



The method of righting, described by Romanes and Preyer 



e,c 



seems to be confined to Astropfroien and its allies. I hav 

 never had access to one of these species and therefore shall 

 regard this highly specialised sand burrowing group as outside 

 the scope of the present paper* The peculiarities of their 

 righting reaction are said (Romanes 188$) to be contingent upon 

 the fact that the tube feet are not equipped with suckers and 

 hence do not attach* 



Description the riiditimt reaction as oosurs yhen the 

 tube feet are prevented attaching by inverting the animal o* 

 sand. 



With the animals at my disposal it was thought possible to 

 prevent the attachment of the tube feat*' by investing upon sand. 



2he behavior of a large sluggish Pitas ter .when inverted 

 on earn is interesting in connection with Moors (1916, 1918, 

 1920# 19204) recent observations on strychnine poisoned starfish* 

 The tube feet at the tips of all of the rays of the large sluggish 

 animal* I had under observation extended out toward the tips and 

 the rays bent dorsally, setting themselves more nearly at right 

 angles to the actively extended tube feet* The tube feet 

 however did not attach as they came in contact only with sand* 

 The coordination of tube feet did not spread back very far and 

 the dor so -flexion involved only the distal pats of the rays* 

 Tor some time all five rays remained donro-flexed* 'tfhen the animals 

 we*- placed on 1t$s ventral side on the sand, there was still ?very 

 marked tendency for the rays to 11 bend dorsally at the tips* 



Now hen a similar specimen, large and sluggish, was placed 

 in a dish of strychnine sulfate in sea water 1*10,000 the same 

 picture appeared, with the additional factor t at the tube feet 

 suckers were so paraliaed that they could not attach to a solid 

 substrate* There was then, a tendency toward dorsoflexion at 

 the tip of the rays and a failure of the coordinated impulse to 

 spread readily among the tube feet as a result eiffi.r -f the paralys* 

 of the tube feet by strychnine and of prevention of their attachment 

 on sand* 



These results are probably merely analygous to those of Moore 

 on As ten. an forbeai and tend to demonstrate the many ways in which 

 a givoii response may be brought about in the various pxx represen- 

 tatives of the asteroidea. I have, moreover, so far been unable 

 to get in yisaster the marked dorao-flexion which Moore figures 

 for Aateria lesi. 



