is possible 'in all directions. This mechanism is 

 aided in producing the locomotion of the creature < 



not only by the arm spines where they are present 

 but by the Toot tentaclesi.TheseTlatter organs, which 

 are the homologu.es of the tube feet or other echini 

 oderms,have been previously regarded as having given 

 up their locomotor function entirely but I shall show 

 further on that this is not true in the genus OPhiura 



The experiments I carried on last Summer on the 

 movements of ophiurans resulted in little that is 

 new, but oh account of the confirmation my notes and 

 photographs give to PREYERS work ( ) on the same 

 subject ,it has been thought advisable to publish 

 them. 



ot?t/ The usual method of progression ha for one arm 

 4rd precedent taking no other part apparently than 

 to point out the way • the two arms adjacent to and 

 behind the anterior arm make the stroke, the remain- 

 ing arms are dragged behind acting as a rudder .Fig. 1. 



No preference as to which arm should prec 

 could be found in an adult ophiuran each arm being 

 equally capable of going before , making the stroke 

 or following behind. 



If greater speed is needed, for example, to get 



