200 



specimens, the included valves are most probably involved in spathose 

 matter, which has crystallized within the tube. 



Plate XIV. Fig. 7, is a very instructive specimen of this shell : the 

 valves being there seen partly denuded of their including tube. This 

 specimen I purchased from the Museum of Dr. Menish. It was found 

 at Bradford, Wilts, in the white clay which covers the great Oolite rock. 



1 have now before me a fossil of this species from Malta, of which I 

 have opened one side so much, as to give a pretty fair view of one of the 

 valves, which is very nearly two inches in length, and has a very smooth 

 surface. This shell evidently differs from the Bradford shells, Fig. 2 and 3, 

 which again differ from each other, they forming, as it were, sub species., 

 I have been favoured witfr calcareous masses, in which these fossils are 

 imbedded, from Bedfordshire, by Mr. GoodhaM and the Rev. Mr. Marsh; 

 and from Wiltshire, by Mr. Cunnington. 



In the F. tibialis, which is much larger than F. ampullaria, one of the 

 valves is found adhering to one side of the tube. This valve is marked 

 with unequal transverse striae, which a magnifying glass shows are decus- 

 sated by longitudinal, and sometimes punctuated striae. The lower part 

 only of this tube has been seen by Lamarck ; and this seems, to bear some- 

 what of the general form of the preceding species, although much larger. 



In F. echinata, the bulbous end of the tube is irregularly beset with 

 tubular points. On one part of its surface, which is bounded by a fringe 

 of these spines, there occurs a small smooth space, and then another sur- 

 face, beset with spines. On the other side, one of the valves is detected, 

 set in the side of the tube. This valve, though apparent^ smooth, is 

 discovered, by the glass, to be beset with minute scaly points, disposed 

 in rows, x directed towards the beaks. This fossil, as well as the other, 

 was found at Grignon. 



F. per sonata is very remarkable for the form in which its larger, or 

 clubbed end/ terminates. The tube, which is cylindrical in great part 

 of its length, is seldom more than two or three inches long-; becoming 

 small at its open end, and being somewhat rounded at the other. At 

 this larger termination it is closed, rounded, and very obtuse ; and on 



