WHEEL-BEARERS 298 _ 



motion is sensibly retarded; it now and then adheres to 

 the glass momentarily, by its foot, and moves forward by 

 successive jerks, not proceeding more than its own length 

 at a time, and this apparently with effort. The periods 

 of its remaining stationary become longer, so that you may 

 suppose it finally settled two or three times, before its 

 wanderings are quite over, some shock or alarm sending 

 it off to a little distance again. 



At length it wanders no more; its foot holds fast to 

 the glass, and its movements are confined to whirlings 

 round and round on this as a pivot, and to sudden con- 

 tractions of length. Presently we see a very delicate film 

 surrounding the point of attachment the first rudiment 

 of the tube, a ring of mucus thrown off from the skin, 

 and pressed down to the foot by the contractions of the 

 body. Meanwhile, the ciliary crown is dividing itself into 

 two, and now we see already the essential form and appear- 

 ance of the mature animal, every moment developing its 

 perfection. 



