I am disposed to consider as P. campecliensis, List. Conch. Tab. 

 Fig. 275. 



C XX VIII. Fistulana. An equivalved bivalve, gaping, nearly tooth- 

 less shell, included in a club-formed testaceous tube, open at the smaller 

 end. 



The bivalve of the Fistulana, as may be seen by its representations, 

 Plate XIV. Fig. 2 and 4, bears a considerable degree of resemblance to 

 the valves of Modiola : and it should be recollected, that some of the 

 Modiola, Mytilns Lithophagus, Linn, for instance, are found in cavities 

 formed in stone. The tube of the Fistulana is completely closed at its 

 larger end; whilst the smaller end is open, and has sometimes one side 

 of it formed by one of the valves adhering to it. 



We are much indebted to M. Faujas St. Fond for his researches re- 

 specting these fossil bodies, and for ascertaining the existence of these 

 bivalves in their proper tube among the fossils of Grignon. 



Lamarck describes four species of this genus as found fossil in the 

 neighbourhood of Paris : F. ampullaria, F. tibialis, F. echinata, and F. per- 

 sonata. 



The first of these, F. ampullaria, the tube of which is of the form of 

 an elongated pear or bottle, and covered by a calcareous sand, has two 

 ridges in the inside of its smaller part ; and in this part is found the bivalve 

 shell, resembling one of the modiolae, and with a shining surface. The 

 shell is sometimes found loose, and at other times united to the tube by 

 interposed spathose matter. 



Mr. Meade very kindly favoured me with the two shells of this genus, 

 detached from their tubular parts, the representations of which have been 

 just referred to. The same gentleman also obliged me with a mass of 

 spathose lirne-stone, in which several of these fossils are imbedded, with 

 their containing ampullaceous tube. Plate XIV. Fig. 6. 



The fossil which is figured Plate XII. Fig. 1, of the second volume of 

 this work, to show its coralloicl investment, as well as the ampullaceous 

 bodies in Fig. 2, of the same plate, belong to this genus, and doubtlessly 

 contain the two valves composing the shelly but here, as in many other 



