IO VERRILL 



other, yet all the vast number of suckers, sometimes 20,000 or more, 

 and all the rays must act in unison or there could be no progression, 

 nor any procuring of food. 



Just how starfishes decide to travel in one direction rather than 

 in another is a problem difficult to solve. 1 



Dr. Jennings, who has experimented extensively with reference 

 to the behavior of starfishes, says very truly that whatever a starfish 

 can do at all it can do in many different ways and seldom does it 

 twice in just the same way. This is particularly applicable to its 

 modes of righting itself when turned over, getting out from under 

 weights, elastic bands, etc. He found that when a starfish had been 

 forced to use the same arms to right itself very many times and for 

 several weeks, it could thus be trained to continue to use the same 

 arms, and thus had acquired a new habit, but if left to itself it lost the 

 habit in about a week. 



Perhaps the preference of the starfish to use the same rays was 

 mainly because, by repeated use, the muscles of those rays had become 

 somewhat larger and stronger by the systematic " training." 



I know of no other successful attempts to educate a starfish. In 

 nature they seem to show some memory and some persistency. I 

 once placed a large active holothurian (Thy one briar eus], that I 

 wished to figure, in one end of a large aquarium, about four feet 

 long, while there was a starfish (Asterias forbesi) at the other end. 

 Next morning the starfish was mounted on the Thyone and had 

 slightly eroded its skin by means of its oral spines. I disengaged the 

 Asterias, put it at the opposite end of the tank with stones and other 

 obstacles between, and supplied other food, such as cracked mus- 

 sels, etc., and other Thy ones, apparently just as good. In a couple 

 of hours it was back again, working away at the same spot on the 

 holothurian. The same course was taken a second time, with the 

 same result. The starfish was evidently bound to eat that particular 

 Thyone or go without any dinner. I had to remove it from the 

 tank to save the Thyone. Apparently the Asterias either remem- 

 bered where his chosen dinner rested, or else it had a keen sense of 

 smell to distinguish it from others of the same species, and from 

 other natural food. 



In respect to maternal instincts, the most interesting case known 

 to me was told to me by Prof. Louis Agassiz, while I was a student 



' Dr. L. J. Cole ( Journ. Exper. Zool, xiv, No. I, 1913) has recently made 

 some interesting experiments on the behavior of Asterias forbesi under 

 special conditions, as to the relative use of the various arms as anterior or 

 directive, etc. 



