266 SERPULID^. 



SO distinctly separated into sets. Anal segment small and entire, 

 with a terminal orifice ; and underneath it a long white spot pro- 

 duced, perhaps, hy some dilatation of the intestine. 



The shell is from 4 to 5 inches long, and as thick as a goose-quill. 

 It is cylindrical, gradually tapered at the posterior end, where it 

 becomes more or less flexuose, and where it is affixed to the foreign 

 body whence it takes its origin. The colour is opake white, and the 

 smooth surface is usually encrusted more or less with Lepralice, 

 Celleporce, and small kinds of Serpula. The margin of the aperture 

 is circular, smooth and even. 



I kept the individual here figured for several days by me, to ob- 

 serve its motions. The worm would sometimes remain for hours 

 concealed in the shell ; and, when it ventured to peep out, the bran- 

 chial tufts were sometimes slowly and cautiously protruded, and 

 sometimes forced out at once to their full extent. After their extru- 

 sion, they were separated and expanded, as in the figure, and lay at 

 perfect rest on the bottom of the plate, in unrivalled beauty, and an 

 object of never-failing admiration. The worm, however, seemed 

 never either to slumber or sleep ; for, on any slight agitation of the 

 water, occasioned, for example, by walking across the room or leaning 

 on the table, it would at once take alarm, and hurriedly retreat 

 within the shelter of its tube. It was never off its guard, and would 

 often, when lying apparently in calm indulgence, suddenly withdraw, 

 in evident alarm, without a cause but what was gendered by its own 

 natural timidity ; for the phantoms of dreams are not, it may be, 

 the visitants only of higher intelligences, but come as they like, in a 

 fearful or cheerful mood, even to these lower things. It never pro- 

 truded itself farther than is shown in No. XLV. a ; and, after 

 becoming weak and sickly, it first threw off one half of its pride, a 

 branchial tuft ; and after several hours the other was likewise cast 

 away, when the poor mutilated creature buried itself, still living and 

 to live for a day or so longer, in its own house and cemetery. 



The anus is at the posterior extremity, as in other worms ; but 

 the remains of its food are ejected from the mouth of the shell, in 

 small egg-shaped pellets. By what contrivance this is done, I do 

 not know ; are the pellets forced along the dorsal furrow ? The 

 fan-shaped fascicles are its breathing organs ; and the brushes of 

 bristles in the sides of the mantle are the organs which enable it to 

 move up and down the tube, assisted, undoubtedly, by the rough 

 spots on the margins of the body. This is traversed down the centre 

 of the back with a vessel filled with red blood, and which sends off 

 minute branches to almost every ring. 



Mr. Berkeley has attempted to draw a distinction between Serpula 

 arundo and tubularia. The former, he says, maybe known "by its 

 more slender form and delicate substance ; neither is the aperture 

 expanded, as in S. tubularia. The animal differs from S. tubularia 

 in its oblong dorsal area ; while that of the latter is much attenuated 

 behind, and in the absence of the operculum." Now, if we turn to 

 Montagu, the original describer of S. tubularia, and whose name 

 therefore ought to be retained, we shall find him telling us that the 

 animal has no operculum ; and his description of it agrees exactly, 



