2 
in Mag. Nat. Hist. vol. 8. 562. P. Bivonae, 
Phill. Enum. Moll. Sicil. 8. PI. II. f. 1. Smith , 
Mem. Wern. Soc. vol. VIII. 23, 45 and 49. t. 2. 
/. 4. P. Spengleri, Valenc. Arch, du Mus. 
d’ Hist. Nat. vol. 15 and 34. PI. V. f. 3. 
Var. j3. Nana. Flatter and smaller than a. 
This Panopaea varies much in form, sometimes being 
truncated in one direction and sometimes in another, at 
other times being hardly truncated at all. The var. « is 
living in the northern seas of Europe*; it is also found fos- 
sil on the Isle of Bute and at Palermo. The var. /3, which 
is the one before us, is found in the Red Crag at Sutton ; 
its small size indicates that it had not been in a congenial 
situation for some time before it ceased to live ; it is also 
often variously thickened and distorted, but not so much 
so as several of the large variety, which occur in their na- 
tural position in the sandy clay raised above the level of 
the sea on the shore at Ruduback Farm on the Isle of Bute, 
where they were found by Mr. G. B. Sowerby in company 
with James Smith, Esq. of Jordan Hill, in 1838. (See the 
Transactions of the Wernerian Society above-quoted.) 
The large as well as the small varieties are subject to a 
diseased thickening of the shell, and seem to have strug- 
gled against a change of circumstances, (we can hardly sup- 
pose of climate,) unless it were an increased temperature, 
for the species is still found living and healthy in the north- 
ern seas, where it appears to thrive in deep water, and 
would probably be rendered sickly by being brought into 
shallow water, or perhaps by an accession of fresh water. 
The specimens I have from Palermo do not appear so 
much diseased ; they were probably more suddenly acted 
upon. The dwarf variety before us had perhaps been long 
subjected to such a change as we have spoken of before the 
disturbance took place that reduced it to the same state as 
the older Crag Fossils scattered upon the shores where it 
supported a feeble existence with difficulty. 
* Shells dredged up on the Yorkshire coast are made into snuff-boxes 
by the fishermen. 
