86 LUCINIDA. 
was met with, close in shore, at Littleham Cove. Though im- 
mediately put into water no organ was exserted, except at the 
centre of the ventral range a small portion of a pomted foot. 
As the animal continued apathetic it was opened, when a 
large corrugated subcylindrical foot became visible, which on 
being divided proved to be tubular, but near the body it 
appeared slightly geniculated. On each side there was one 
rather elongated branchial plate, apparently divided by the 
branchial artery in two portions; these were connected and 
doubled on each other, forming one thick plate, of a darkish 
brown colour, shot with a hue of pink, very closely and 
strongly decussated by the branchial vessels. No palpi were 
seen. The liver is brownish-green. The margins of the shell 
are plain, and the edges of the mantle loosely smuated. The 
posterior adductor scar is pyriform, the anterior one narrow 
and strap-shaped. Of the two primary teeth in each valve, 
one of each is cloven; there is also an anterior lateral one in 
both valves. 
Another specimen has this year (1853) occurred, of the 
same size, and at the same habitat. It proved lively, and 
has enabled me to offer some additions and explanation. The 
foot is very narrow but lancet-pomted, and when fully ex- 
tended is nearly as long as the vertical measure of the shell ; 
it is always in the first mstance exserted from the ventral 
central point, and from thence can move itself anteally to a 
right angle. It is transversely and longitudinally wrinkled, 
and when alive has the aspect of bemg roughly shagreened ; 
when dead it appears intensely corrugated across and length- 
ways; it has a decided heel near the junction with the body, 
and is beyond doubt tubular to within a short distance of the 
termination, and possibly may be entirely perforated. I made 
with the scissors two sections before the tubular structure was 
visible, but in so delicate an organ the pressure of the knife 
might close a real perforation, which I believe exists ;—not to 
admit water either to the branchiz or viscera, as some natu- 
ralists think, but to render the foot a potent locomotive organ 
by inflation, and having the power of opening and constricting 
the perforation for the issue and admission of the water. The 
