SERPULA. 



jespects very vague and indeterminate : seeing moreover 

 that the shell differs in no material point from that of 

 Serpula, we have thought it hest to unite the whole toge- 

 ther under the old appellation : at the same time we will 

 point out the particular marks hy which Lamarck has 

 distinguished them into four, we might say five genera, 

 for we have already shown that Galeolaria might with 

 propriety be united to Serpula. The peculiarities of La- 

 marck's Serpula are, irregularly convoluted, grouped or 

 solitary tubes, with a round very simple aperture: the 

 shell of Spirorbis is twisted into an orbicular discoidal 

 spire, the lower surface of which is flat and attached; its 

 aperture is also orbicular: the Fermiliae are attached by 

 the side of their shell, repent, with a round aperture whose 

 margin has from one to three teeth : Vermetus is known 

 by its having the commencement of its shell formed into 

 a regular pointed spire, attached at its smaller end ; in 

 other respects it is like Serpula. Our Serpula, uniting the 

 whole of these, may be characterized as follows : 



Shell tubular, cylindrical, increasing gradually in 

 size, either forming a regular, pointed, of an orbicular, 

 discoidal spire, or irregularly convoluted : sometimes at- 

 tached by its flattened lower surface, sometimes repent 

 without a distinct spire, sometimes only attached by a 

 part of its shell, the remainder being somewhat irregu- 

 larly erect and undulated and variously twisted ; and very 

 rarely almost free : aperture for the most part round, its 

 margin either simple or having one or more teeth or an- 

 gular prominences, according to the number of ridges 

 outside the tube : operculum shelly or horny, orbicular, 

 and very variable in its form; the outside of these shells 

 is also exceedingly variable, being either annulated, im- 

 bricated, ribbed, corrugated, subspinose or smooth. There 

 are also some other variations to v/hich the Serpulae are 

 subject, which might have formed the foundations of new 

 genera, with as great a degree of propriety as any of 

 those separated for the reasons we have detailed above : 

 the principal of these varieties that we recollect are, 

 those with an expanded aperture; those with a very 

 contracted opening, like a narrow fissure; those which 

 spread laterally on both sides wherever they are attached;^ 

 and those which form a groove in the shell or other 

 substance to which they are attached, and lie as it were 



