THE TENTACLES. 211 



Both the stalk and the head now develop themselves 

 in length and thickness, until the stalk attains a 

 length of ahout -j^ inch, and a thickness of ahout -^. 

 The head or body of the Polype has now become 

 somewhat bell -shaped, more gibbous, however, at one 

 side than elsewhere; and this side, for distinction's 

 sake I shall call the back. The edge expands into a 

 wide circular disk sometimes slightly reverted, around 

 wdiich are set, a little within the extreme rim, four- 

 teen rather short cylindrical tentacles, separated from 

 each other by somewhat more than their own width. 

 They do not expand (so far as I have seen) beyond 

 the limits of the disk, but rising perpendicularly 

 from the edge, they curl over their tips in an elegant 

 manner towards the common centre. The sides of 

 these tentacles are set with delicate cilia (Fig. 2), the 

 waves of which pass up on one side and down on the 

 other. I think that the cilia are confined to the sides, 

 for at either edge of the tentacular circle, where the 

 exterior came between the eye and the light, I could 

 not detect the least ciliary action. By means of the 

 motions thus produced I saw minute, floating parti- 

 cles drawn within the disk, and others shot forcibly 

 out. 



The tentacles do not appear to be capable of con- 

 traction or elongation, but when expanded their in- 

 curved tips are continually being thrown inward, so 

 as to increase the curl, and again opened. This 

 action, which is almost constantly being performed, 

 is a little spasmodic jerking or grasping, very slight 

 in its degree. When alarmed, however, they are 

 drawn inward by the common contraction of the 



