209 
NUCULA pectinata. 
TAR CXCII. — Figs. 0 and 7. 
Spec. Char. Transversely elliptical, elongated,, 
convex ; posterior side truncated ; longitudi- 
nally furrowed; lunette imbedded, flat, cor- 
date ; edge crenulated. 
This is a large species of Nucula; its surface is co- 
vered by small diverging furrows, which are crossed by 
line transverse striae : the lunette is very conspicuous and 
broad. The specimens are not so opened as to shew the 
hinge pit, but I think it may be traced in the casts. 
I am indebted to W. Borrer, Esq. an enlightened Bo- 
tanist, for specimens found in clay in Sussex, long since. 
I have also received several from Folkstone and Dover, 
where they are abundant in various states. The shell is 
tender, and filled either with argillaceous Ironstone, or 
Pyrites : when the shell is decayed there remain neat 
casts of the inside, shewing the teeth and the two mus- 
cular impressions of each valve, which must have been 
deep in the shell, as the casts of them are much elevated. 
The shell is pearly within. The two figures 7 are diffe- 
rent views of a cast in Ironstone of a similar but wider 
shell, in which the anterior side is more acuminated ; 
probably this form is produced by the compression of the 
two valves together. 
NUCULA minima. 
TAB. CXCII.-— Figs. 8 and 
Spec. Char. Transversely ovate, convex, trans- 
versely striated ; posterior side acuminated ; 
edge entire ; lunette defined, elongated. 
N early twice as wide as long ; the lunette is straight, it 
reaches from the beak to the angle of the posterior side : 
