FISTULANA. 



his F, Lagenula, a specimen of which we have sacrificed 

 for the purpose^ we find it accords in every character with 

 Gastrochcena, it must therefore be removed to that Genus; 

 the next species that claims our attention is F.ampullaria, 

 this we have never seen : Lamarck, however, informs us 

 that its " aperture is bicarinated within/' a circumstance 

 which proves this also to belong to Gastrochcena^ next 

 comes his F. Pyriim, of which the only character he men- 

 tions is that "the external tube is pearshaped and naked," 

 in which respect it accords more perfectly with the Gas- 

 trochcena than with the type of Fistulana, we think, there- 

 fore, that this ought also to go into GastrochcEna. 



Let us now proceed to Lamarck's second and third 

 species ; the first of these, namely Fistulana corniformis, 

 judging from the characters of the shell which he gives 

 and the figure of the animal to which he refers, must be- 

 long either to Teredo or Teredina'*, we think Teredo, be- 

 cause the phrase " aperturd anticd tubulis duohus inclusis 

 divisd" not only supposes the tube to be open at both ends, 

 but in otlier respects forms an important part of the cha- 

 racter of Teredo : to which circumstance may be added, 

 that the valves in the figure exactly resemble those of 

 Teredo. We think Lamarck's third species, Fistidma 

 gregata, belongs to, and should form the type of, Teredinay 

 because it has the same general form; the internal valves 

 are of the same shape, and are also placed in the same 

 situation, and further, because it is closed at the larger 

 end, as Teredina personata evidently is. Thus we think we 

 have disposed of Lamarck's last five species; there now 

 remains only his first species, Fistulana Clava^ (which must 

 be considered as the type of the Genus,) and those species 

 whose valves bear some resemblance to those of Modiola. 

 We have seen many of these latter, and consequently, 

 from actual observation can assure our readers that they^ 

 are Lithodo7ni\ which have lived in Madrepores, and, 

 which in consequence of a very peculiar circumstance 

 have been ranked among the Fistulance, Difficult as it i^,^ 

 we must endeavour to explain this circumstance : we have, 

 shown in a former Number that the Lithodomi, though^ 



* Lamarck's Teredina personata is a cast of the inside of a tube closed 

 the larger end, like that of his Fistulana gregata. We think his Teredina Ba- 

 cillum is a Saxicava. 



■\ Or Saxicavce, or Gastrochcence, 



