NO. 19.] ECHINODERMS OF CONNECTICUT. 75 



so-called memory of past stimulation is lost under the influence 

 of a much stronger stimulus, such as bright light, from which 

 the animal retreats rapidly. 



The behavior of the ophiuran when subjected to a great 

 variety of artificial conditions has been studied by Glaser.* 

 The animal's ability to solve to its advantage many of the prob- 

 lems set for it, such as removing rubber bands from its arms, 

 for example, illustrates a high degree of nervous coordination. 



Regeneration. — The rays of all our species are fragile, and 

 are so likely to be broken off in handling, that in some species it 

 is difficult to kill and preserve a specimen without mutilation. 

 Some of the species voluntarily throw off one or more rays at a 

 point close to the disk if the animal is even slightly irritated 

 by rough handling or by being placed in a fluid not to its liking. 

 Other forms when disturbed break off the arms piece by piece 

 until nothing of the animal remains except the disk. 



When one or more rays are accidentally or voluntarily broken 

 off in a state of nature, the wound quickly heals and new rays 

 grow out from the disk in place of those destroyed, as in the 

 case of the starfish. 



If a ray is broken at some distance from the disk the end is 

 restored to the normal length. Individuals are often found, as 

 illustrated on Plate XII, which show such rays in process of 

 regeneration. If the disk is cut in two each part is capable of 

 regenerating a complete animal. 



Certain species, such as Amphioplus abditus, have the remark- 

 able habit of throwing off the disk when strongly stimulated, 

 leaving only the mouth frame attached to the arms. Under 

 favorable conditions the missing parts can be regenerated. In 

 Amphipholis squamata, in which the young develop in the genital 

 bursse, this process of throwing off the disk is said to be the 

 normal method by which the young are discharged. 



FOOD 



Because of their secluded and nocturnal habits it is difficult 

 to determine the exact nature of the food on which the ophiurans 

 subsist. The animals are seldom seen to take any food whatever 



* Movement and Problem Solving in Ophiura. Jourtt. of Exp. Zool., vol. iv, 1907- 



