UNIVALVES SERPULA. 115 



The Serpula Gigantea sometimes grows to half-a-foot 

 high, and about the thickness of a finger. The Serpula 

 Lumbricalis, or Cork-screw Shell, is flexuous, and has a 

 spiral acute tip, very much resembling the article after 

 which it is named. The Serpula Filograna is branched 

 and complicate, and is adorned with a beautiful kind of 

 net-work. 



One of the remarkable species of this genus is the Ser- 

 pula Anguina, which has a split or long-jointed cleft, all 

 along the spiral convolutions of its shell. The Serpula 

 Echinata has its shell beset with a succession of spines or 

 prickles; it is usually of a rosy or pink color, and some- 

 times has its aperture margined. 



The Serpula Comucopiae^ or Horn of Plenty, is, in all 

 probability, only a dropped Helix Hortensis, or common 

 Garden Snail, and of course not belonging to this genus. 



The Serpula Infundibulum appears as if its first bend 

 was composed of five funnels, inserted within each other. 



The Serpula Denticulata is sometimes found in the Le- 

 pas Tintinnabulum ; and the Serpula Sulcata adheres to 

 the roots of the Fucus Digitatus. 



The Serpula Lagena is exactly like an oil-flask, and 

 the Serpula Retorta is retort-shaped; the latter is scarce. 

 The Serpula Incurvata something resembles the Nau- 

 tilus Semilituus, but it wants the internal concamerated 

 structure. 



The Serpula Nautiloides is a spiral shell, flatfish, mi- 

 nute, and is furnished with thin, semilunar, internal divi- 

 sions. 



The colors of the Serpulse are various; the most gene- 

 ral, however, are brown, purple, yellow, tawny, pink, 

 and white, sometimes a little greenish. The Serpula Se- 



