126 STRUCTURE OF BREATHING ORGANS. 



In one of the marine tanks in the Eegent's Park Gardens, there 

 stood for a long time a common glass bottle completely encrusted 

 with the tortuous tubes of various species of Serpula?, but chiefly 

 with those of the one just mentioned ; and when the worms were 

 all protruding, and their brilliant plumes displayed abroad, the 

 bottle presented an extremely curious and beautiful appearance, 

 as though it had been overgrown by some strange ungainly plant 

 of ocean, leafless, but decked with gorgeous flowers. 



These flower-like expansions are the Serpula's breathing organs, 

 and consist of a series of stiff threads, arranged in the form of a 

 funnel deeply infolded on one side, and beset on their inner sides 

 with a double row of minute bristles like the teeth of a comb. 

 In the centre of this brilliant array of branchial plumes there is 

 a curious stopper-shaped body seated at the end of a long slender 

 stem, which serves the purpose of a trap-door to the Serpula's 

 domestic establishment, and neatly blocks up the entrance when 

 the little worm finds it convenient to retire out of sight. It does 

 this with wonderful celerity, and at the slightest alarm ; for 

 though the Serpulae belong rather to the " still life" of the Aqua- 

 rium, so long as all things remain quiet, let some eager gazer give 

 the vessel but the slightest shock, and, quick as thought, the 

 little beauties start back into their tubes, leaving their would-be 

 admirer in open-mouthed wonder at their sudden disappearance. 



Notwithstanding that the Large and showy species of Scrpula 

 already named is almost universally regarded as the beauty of the 

 race, we are by no means sure that the quiet, unassuming grace of 

 the little triangular-tubed species (& triquetra) does not entitle 

 it to a higher place in our favour. It is small in size, it is true, 

 and not very gaily coloured, but the rich tints of brown, gray, 

 and ruby with which its branchial plumes are mottled and banded, 

 give it a very elegant appearance when viewed with a lens, while 

 its operculum or stopper is shaped very much like the cup of the 

 well-known toy, the cup and ball. On first looking at a group of 

 these curious Annelids in a well-kept Aquarium, the observer is 

 pretty sure to be struck with the perfect stillness which they 

 maintain, and the idea of a cluster of flowers is instantly sug- 

 gested to the mind. But within a moment or two, in all pro- 

 bability, the long whip-lash extremity of one of the bristles will 

 be seen to give a sudden twitch, then the bristle itself is slowly 

 raised, then another and fnother partakes of the movement, and 



