ON I HI. RIGHTING MOVEMENTS Ol TNI. STARFISH .' 



A. R. MOORE. 



In an iirtirlc entitled "The Behavior of the Starti-h, Aster ins 

 For re r i de Lariol," 2 Jennings discusses the movements of that 

 aniinal in righting itself. He assumes that tin- -tarfi-h makes 

 it- IIK.M mi nts in order to adapt itself to it- environment and 

 that t re these movements are purposeful. 1 "mm thi- as- 



sumption he concludes that "when the starfish is turned over on 

 ii- dor-al surface locomotion is impossible, the finding and capture 

 -f fo.-d must stop; the delicate gills are pressed a^ain-t tin- l.<.i- 

 loin. injuring them and impeding respiration; and di-plat t un -m- 

 oi tin- inicrnal organs must occur that may be harmful io their 

 per functioning. We find, as might lie anticipated, that tin it- 

 is a regulation of these bad effects by movement: tin -tarii-h 

 turn- again on it- \ ntral -urface.' 



A much simpler explanation of the righting mo\ement- h.i- 



IM-III given by I.oeb.' He points out that the ttil-c ire 



iti\ely stereotropic. Therefore the arms twist and turn until 



all of tin tul't- feet are in a position to be in contact \\ith a 



Mirfai 6. 



I have ma< le >l>servations on about thirty specimen^ < >\ A stcritm 

 minnita and a like number of Asterias ochra<i. \\ith a \'ie\\ to 

 determining the nature of the righting movement-. 



lit n- look tir-i at the cau-es, which Jenniiu- ha- ^i\eii u~, 

 tor the -larli-h riv;litinv: ii-elf. 



In regard to the tir-t, \i/.. that locomoti<'ii i- one of the ends 

 which a -tarti-h ha- in \ iew in righting it-elf, I ha\f found that 

 \ei\ tret|iientl\- the starfish crawls up the -ide of the- aquarium 

 and, upon reaching the -urfare of the \\ater, thru-t- out three or 

 four arm- dorsal side downward, their tube Icet clin^ini; to the 

 surface film of the \\ater. In >udi a po-itioii the> n-mained 



l i. 'in tin- I rchLaboi ' .il. 



. Vul. 4, pp. .vi 1 85. 



I (X !| . rative l'h>>ii>ln>;y nf tin- Hrain," ('luipti-r 3. 



