13 
'hin as a film, moro especially towards the anterior part. 
*et even in its very immature state, the tube of this species 
near the tail, some distinct testaceous chambers : showing 
' le fact that the body makes some progress beyond simple 
§ r owth : a circumstance less clearly established in the com- 
mon Auger Worm. The chief, or at least, the most clear 
j^d easy distinction between this species and T. Navalis will 
J ° found in the structure of their jaws : the cutting portion 
which, or triangular projection, in the latter species being 
!L e nt obliquely downward, but not nearly so much so as in 
,*• Malleolus, In T. Navalis, fine, slight, closely placed 
,n es radiate backward from this point to where the upper 
P°rtion of them joins a series of similar striee that pass upward 
1? an arched manner, each line turning off backward into a 
a t space which ends abruptly. The jaws of T. Malleolus 
are more glossy, and the divergent lines of the triangular 
P°ftion are less numerous and more distinctly separate ; the 
being more prominent, with wider spaces between them. 
t l le perpendicular lines also, which run at right angles to 
former, are also more distinct, though examined in a 
jjmch smaller specimen ; and turn off backward in separate, 
J 11 not as in the former, in wide arches. 
*\NANA. Flem. Brit. An., p.455; whose sole authority 
I s Turton. The shell is four tenths of an inch in diameter, 
lQ both directions, though too irregular to be termed 
r °nnd ; very deep in the hollow, almost globular. A 
lender, but very distinct rib passes round the concavity, 
f r °m the slight but firm oblique tooth at the portion that is 
ln curved, to" the opposite margin. This rare species was 
f °nnd in a piece of oak, thrown on shore at Gorran : com- 
municated by Mr. Peach. 
PHOLADARIA. 
e Shell without a tubular sheath, gaping anteriorly ; ligament 
Vernal, and with accessory pieces of shell not belonging 
0 the valves. 
PHOLAS. 
ENllRlC CHARACTER : Shell bivalve, equalvalved, 
transverse, gaping at both sides, having accessary pieces 
a ffixed above or below the hinge. The inferior or pos- 
p teri or margin of the valves reflected outward. 
• DAdTYLUS. Turt. Lin. Borlase’s Nat. Hist. Corn., 
P'- 28, fig. 3I . Pen. Brit. Zo., vol. 4, pi. 39, fig. 10. 
Mont. Test. Brit., vol. 1, p. 20. Flem. Brit. An., p. 457. 
. u's shell is a borer, commonly of the hard rock, in which 
11 lives at ease, and by which it is protected from injury. 
. nave only seen it as taken from slate rock on the west 
s >de of Pridmouth Cove, not far west of Fowey. 
