LOCOMOTION OF BERMUDIAN MOLLUSKS 227 



folded over and attached to both surfaces of the glass at once. 

 The animal would then move forward keeping the posterior 

 part of the foot still in contact with the other side of the plate, 

 until gradually the whole foot was on the other side. Cypraea 

 moved with greater velocity under these circumstances than at 

 any other time. The average rate was 1 cm, in four seconds. 

 It was noted that the anterior 2 cm. of the foot seemed fairly 



Fig. 1. Cypraea exanthemia L. viewed from beneath. The animal is turning 

 to its left. Four anterior lateral waves (dark curved areas) are moving to the 

 animal's left, and three posterior lateral waves to its right. 



free from mucus, while a large amount was secreted by the rest 

 of the foot. It may be that the anterior edge of the foot is thus 

 specially modified for the act of attaching the animal to the 

 substrate by suction, and perhaps also for the reception of the 

 stimulus which leads to the attaching reflex. This behavior is 

 in contrast to that of Chiton and other mollusks, where any 

 portion of the foot will become attached to a surface (Parker, '14). 

 But the most striking phenomenon about Cypraea's locomotion 

 was the diversity of directions in which the pedal waves were 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 24, NO. 2 



