<N THE RIGHTINi, MOVEMENTS OF THE STARFISH. 239 



malformation -if the inactive arm. According to the author cited, 

 such a -tarri-h could be "taught" to use the idle arm by giving 

 the animal a lar^e number of "lessons" ( 180 in one case) in which 

 arm- ordinarily acti\ < were pn A en led from taking hold by "stim- 

 ulatiiu their tube iV.-i with a ;Ja-- r- >d" \\ IK-IK- \ er they attempted 

 to at tach thrm-el\ 



I wa- able to compel -tarli-h of thi-^ -ort to use the idle 

 arm l>y injuring tin- active "in-- in the following ways: (l) 

 Irritating tin- \i-ntral . of the arm by rubbing it \\iih a 



ida-- r>d, j t; the tip- < >f the arm with a fe\\ drop- <-t 



w/io arid. r\v. or thn-e ajplicati>n- a few minute- apart u-ually 

 -ut'tn ed to render the arm inacti\e. In tin- \\a> I \\a-~ able to 

 "teach" the -tarti-h in one "lesson," -|>ontaiH-ou-l\ i.i u-e an 

 arm pre\i.m-l\ inactive. I he length of time the !<.. n \\ as 

 "remembered" depended upon tlie<: t the injur\ . It -eem> 



exident fn.m tin- that Jenni "lessons" c.n-i-ted men-l\ in 



inhibitii'ii- due to the injur\ cau-i-d b\ hi- irritat iii;< the mbe 

 ,,! i he active arm-. lint an inhibition i by a -inde 



or per-i-teiit -limnl.ition i- n..t identical \\ith tin- |>heiiomena >\ 

 A manili--ted in the \<: 



5l MM \K\ . 



i . The righting movements of a -tarti-h whicli ha- been placed 



on it- d"i-al -ide are due only to tin- po-iti\e -ten-ot mpism of 

 the tube I. 



2. An injury t" an arm inhibit- it- beiii;^ u-ed t->r the initiation 

 of i iijitiiii; mi\ einent 



3. A -tarli-h cann-t be taught t" n-e an arm which i- ordinarily 

 passive, but b\ injuring the other I'mir arm- the-e can be pre- 

 \entrd from initiating ri^htin^ mo\enu-nt- and tin- filth arm 

 then initiate- the-e m'\ eiiu-nt-. 



I wi-h to express my -incere thank- t^ Professor Loeb I'-r his 



helpful >u;^e-tious and critici-m. 



