E. W. BERGER ON THE CUBOMEDUS^E. 29 



one stopped pulsating apparently for good upon removing the third 

 club. 



17. All four sensory clubs were removed from one, cutting as 

 high up as possible so as to remove the endodermal tract of nerve 

 fibers of the peduncle. It pulsated afterwards apparently the same 

 as if the stalks had been left intact. 



18. A small piece surrounding a sensory club and including the 

 margin can contract by itself. The piece observed pulsated with 

 quick pulsations and rhythmically but intermittently. After a fresh 

 cutting away of such a piece, the portion of the velarium attached 

 was seen to contract rhythmically, while the rest of the subumbrella 

 was not so seen. The part of the subumbrella above the radial 

 ganglion that was cut off did not contract by itself. The same 

 portion of the velarium cut off did give contractions. 



19. A sensory club with the surrounding region cut out pulsated 

 rhythmically ; when the club was cut from the end of its stalk 

 pulsation stopped. This observation was repeated on another, and 

 contractions were seen after the removal of the club. A piece of 

 the subumbrella wall from the same animal gave contractions now 

 and then even after an hour. 



20. The normal position of a sensory club seems to be with 

 the concretion almost at the lowermost end ; often with it certainly 

 lowermost, but probably oftener with the perpendicular passing 

 through the center of the attachment of the club to its peduncle 

 and just by the inner edge of the concretion. The eyes point inwards. 



When the animal is on its side the concretions are always quite 

 lowermost. When the animal was inverted the tendency was for 

 the concretions to be lowermost. In this position the eyes may 

 point in several directions. In one instance those of one club pointed 

 rather outwards, while of two other clubs they pointed more in the 

 plane of the body wall. (See also Experiments 24, 29.) 



Nerve. 21. Cutting the nerve eight times, once on each side of 

 each sensory club, produced no loss of coordination in pulsating. 

 The animal was weakened, however, by the operation, which was made 

 drastic to insure cutting the nerve; but it was still able to swim. 

 This experiment was repeated four times. 



22. That coordination was continued after the nerve was cut 

 was proved beyond doubt by cutting from the edge up (eight times) 



