WORMS 309 



object; and we may well be thankful to the mercy of God, 

 who has ordained comfort through so strange an instru- 

 mentality. 



The progress of marine natural history, as studied in 

 the aquarium, has made our drawing-rooms and halls 

 familiar with a multitude of curious and beautiful creat- 

 ures which a few years ago were known only, and that 

 very imperfectly, to the learned professors of technical 

 science. Among the forms which embellish our tanks are 

 several species of Serpula, and Worms allied to it. The 

 shelly contorted tube which this painted Sea-worm in- 

 habits, and which it has built up itself around its own 

 body, with stone and cement which that body supplied, 

 is well known to you; as is also the curious conical stop- 

 per with which it closes up its bottle as with cork, when 

 safe at home, and the lovely crown of gorgeously colored 

 fans which it expands when it takes ("the air," I was 

 about to say, but rather) the water. You are familiar, 

 too, with the lightning-like rapidity with which, while in 

 health and vigor, the Serpula, on the slightest alarm, 

 retreats into his fortress, taking care to clap the door to 

 after him. But perhaps you have never had an oppor- 

 tunity of examining the mechanism by which this rapid 

 flight is effected. 



As there are two distinct movements performed by the 

 Worm the slow and cautious and gradual protrusion, and 

 the sudden and swift retreat so there are two distinct sets 

 of organs by which they are performed. Shall 1 sacrifice 

 one from this fine group to demonstrate the mechanism? 

 Well, then, I carefully break the shelly tube, and extract 

 the Worm uninjured. 



Its form is, you perceive, much shorter and more dumpy 



