OF THE POLYPE-TUBE. 317 



slender branch, which presently united again with the 

 main core. The total length was now -^ inch, of 

 which the tube was -tt inch, the diameter of the latter, 

 just below the joint, being about -^ inch. I could 

 not discover, with the closest watching, any circu- 

 lation or other motion among the granules of the 

 medulla. No indication of sensitiveness was given, 

 though an Euplotes with its bristly feet was running 

 rapidly to and fro about the tube, and occasionally 

 crossing the tip. 



The next morning, Aug. 20th, I could perceive no 

 increase over the condition of twelve hours before ; 

 but slight changes in the form of the medulla were 

 taking place, that shewed life was active. Throughout 

 this day I perceived the extremity slowly lengthening, 

 not quite uniformly, but pushing out a portion in a 

 little tumour, the depressions around which would be 

 presently filled up, and the surface would become 

 smooth and round again ; then in a little while, 

 another swelling would appear, which would again 

 be obliterated, and thus the increase went on. The 

 clear opening in the granular core also lengthened, 

 and another formed above it, the two at length 

 merging into one, thus dividing the medulla into two 

 lateral columns ; sometimes a very delicate film was 

 partially sketched across the interspace, which was 

 gradually reduced to a thread as of viscid substance, 

 and then obliterated. 



On the morning of the 21st, the budding portion 

 exterior to the joint was equal in length to that 

 portion below it. (See fig. 7). The young portion 

 appears to be very soft and flexible, for on my incau- 



