FIST ULAN A, 



Lam. 



Gastrochaena, pars, Sj^engler, 



TESTA sequivalvi, inaequilaterali, ad marginem 

 basi hiantissima, latere antico brevissimo ; in 



■ inferiore tubi testacei parte inclusa; tubo an- 

 tic^ (infernfe) clause, postice (superne) per- 

 forate, attenuate. 



Whoever undertakes to remove the confusion that attends 

 Lamarck*s Genus Fistulana will find himself involved in 

 difficulties ft'om which it will he no easy matter to extri- 

 cate himself. This ohservation is suggested hy two con- 

 siderations, 1st. That the greater number of shells he has 

 included in his Fistulana belong properly to his Gastro- 

 chcena, and 2d. That his Ga^trochcena, as we have formerly 

 shown_, belongs to his family of Tuhicolees^ in which also 

 his Fistulana has a place. The confusion appears to have 

 commenced by Lamarck's not properly quoting Spengler's 

 Genus Gastrochcena, which was evidently instituted to in- 

 clude all bivalves inclosed in a shelly tube open only at 

 one end ; and which, according to Spengler's own me- 

 moir, contains some of those species which Lamarck has 

 called Fistulance, together with others for which he has 

 adopted Spengler's name. In executing the task we have 

 undertaken we must endeavour to clear away the super- 

 fluities of Lamarck's Fistulana; we think we shall then 

 leave it exactly what it ought to be, if indeed its existence 

 as a Genus should be admitted at all. We will begin 

 with his three last species 5 and of these, upon examining 



