J 7 
one or two teeth, and a narrow pit for the interna! liga- 
ment. Ligament double; one external, short, the other 
internal, fixed in the cardinal ptts. 
A. COMPRESSUM. Maotra Listeri. Turt. Lin. Stew. 
Elem., vol. 2, p.377. Venus Borealis. Pen. Brit. Zo., 
vol. 4, p. 98. Maotra C. Mont. Tost. Brit., vol. 1, p. 96. 
A. C. Flem. Brit. An., p. 432. On heaps of sand on the 
banks of Looe river, and probably in other similar situ- 
ations; but scarcely abundant. 
* A. PRAETENUE. Mya P. Mont. Test. Brit., vol. 1, 
P- 41. A. P. Flem. Brit. An., p. 432. “ It is not un- 
commonly dredged from Falmouth harbour, but mostly 
single valves.” MoDtagu. I obtained a specimen with 
the valves united. 
A. DlSTOltTUM. Mya D. Mont. Test. Brit.j vol. t, 
p. 42. pi. 1, fig. I. A. D. Flem. Brit. An., p. 432. “We 
first noticed this species at Falmouth, amongst the sand 
dredged from the harbour for manure, and have since 
found it lodged in hard limestone at Plymouth, into which 
it had bored like the Pholas ; probably the occasion of its 
distorted growth.” Montagu. I have found it uot uncom- 
mon in stones from deep water ; and ascribe the distorted 
growth to its occupying holes not made by itself, and 
which in time become too straight for it. Animals which 
form their own habitations in the substance of the stone, 
a re commonly found to enlarge them according to their 
growth ; and maintain the most delicate structure of their 
shells without injury. 
CONVEXUM. Turt. Lin. Flem. Br. An., p. 431. 
Obtained from Mr. Peach at Gorran. 
. Other species arranged by Fleming in this genus, will be 
°ond in the genus Anatina. 
CORBULEA. 
halves of the shell unequal ; ligament interior. 
CORBULA. 
GENERIC CHARACTER: The shell regular, valves 
Un equal, as also the sides ; closed or very slightly gaping. 
One large, conical, curved, ascending tooth in each valve, 
^dh a pit beside it; no lateral teeth. Ligament internal, 
'nserted in the pits. 
' NUCLEUS. Mya Inequivalvis. Mont. Test. Brit., 
1, p. 38. C. Striata. Flem. Brit. An., p. 425. C. N. 
Quarterly Journal of Science, vol. 14, pi. 5, fig. 38. 
Montagu says, “ this shell is by no means uncommon; hut 
arely t 0 b e obtained alive, or with connected valves ; we 
j dVe found it on the coasts of Cornwall and Devonshire : and 
. a living slate dredged from Salcomb bay.” 1 have obtained 
1 1-0,11 Gorran. d 
