29 
glossy ; margin strongly denticulated. We found this 
Uew species amongst sand from Falmouth harbour. Dia- 
meter three quarters of an inch. Although this shell bears 
some resemblance to the young Echinatum, it must not be 
confou tided ; the young of that species is always more 
globose or convex; the ribs are more sharp, and the 
tubercles more pointed and distant.” Montagu. Dr. 
Fleming is disposed to regard it as the young of C. 
, Muricatum. 
c. LvEVIGATUM. Pen. Br. Zo., vol. 4, pi. 51, fig. 40. 
Mont. Test. Brit., vol. 1, p. 88. Flem. Brit. An., p. 423. 
On some parts of our coast, and especially at Hannafore, 
Opposite Looe Island, I find single valves thrown on shore 
'u abundance. 
L FASCIATUM. Flem. Brit. An., p. 422. British 
Museum. Obtained from near the Land’s end. 
HIATELLA. 
Gp NERIC CHARACTER: Shell with the valves equal, 
tile sides unequal, transverse, gaping at the anterior mar- 
gm. Hinge with one small tooth on the right valve, and 
* '*0 rather larger, on the left. Ligament external. 
M. ARCTICA. Solen Minulus. Turt. Lin. Mont. Test, 
“fit., vol. 1, p, 53, pi. 1, fig. 4. H. A. Flem. Brit. An., 
!’• 461. Crouch’s Intro, to Lam., pi. 8, fig. ti. Not 
-Uncommon, burrowed in stone. 
'• PR.EC1SA. Mytilus P. Mont. Test. Brit., vol. 1, 
P‘ 165, pi. 4, fig. 2. Great confusion exists in the writings 
ui naturalists, concerning the two species of Hiatella 
here given, and Saxicava Rugosa ; some supposing them 
l ° be no more than one species, while by others they are 
Se parated into different Genera. Under these circum- 
stances, and having examined them when apparently 
uninfluenced by foreign bodies, l have judged it best to 
ullow the opinion of Montagu, who considers them 
distinct. II. Praecisa is common on rocks near low water 
0la rk, attached to the roots of corrallines by the aid of 
a kyssus. 
Qjp ISOCARDIA. 
* n £RIC CHARACTER : The shell heartshaped, trans- 
verse. ' 
^ gaping at the upper margin, the valves equal, tlie 
entering, cardinal teeth, one of them 
'md er corsc [ et> 
5 * u e . 
' C °R. Chama Cor. Turt. Lin. Mont. Test. Brit. vol. 1, 
pj ’"l 4 - I. C. Flem. Brit. An. p. 418. Crouch’s Intro. 
' !i > fig- 7. Very rare. I have seen a specimen which. 
e aks distant, diverging, spirally turned on one side ; two 
s ' ll > entering, cardinal teeth, one of them curved and 
uuder the beak ; one elongated lateral tooth, situated 
Ligament external, forked on one 
