SILIQUARIA 



TESTA tiibulosa, irregulariter contorta, postice 

 f attenuata, ad basim interd^im spiram regu- 

 larem formans : fissura longitudinali, interdum 

 subarticulata, per totam fere longitudinem 

 usque ad aperturam terminalem continua. 



Sheli, tubular, irregularly twisted, attenuated at the pos- 

 terior extremity, and sometimes forming at the base a 

 regularly convolute spire, strongly resembling a Serpula, 

 but most easily distinguished from that Genus by having 

 a longitudinal, sometimes subarticulated fissure com- 

 mencing near the smaller point, and continuing through 

 its whole length, until it unites with the aperture at the 

 larger extremity. 



Separated from the Linnean Serpula? by Bruguiere, 

 being well characterized by the longitudinal fissure, which 

 there is reason to believe is intended for the passage of 

 the lateral or dorsal branchiae of the animal, consequently 

 proving a remarkable difference in the nature and econo- 

 my of its inhabitant from that of Serpula. Transverse 

 septa are sometimes observable in the tube ; of course 

 these are always posterior to the animal, and shew that 

 as it increases in size, it does not fill the whole length of 

 its tube : we find, therefore, that the fissure is more or 

 less closed behind these septa. The type of this Genus is 

 the Serpula anguina, Linn, to which a few more species 

 are united, none of them known on our coasts. We have 

 reason to believe, that in their natural situation they are 

 attached to and imbedded in a species of sponge or 



