SHORES OF THE CLYDE AND FIRTH. 
97 
the water Avithin bilges up, and the soft feel of the syphon 
seen above the sand is felt below. Continuing, the clearing, 
we find, as far as we go, the rock is completely honeycombed 
with those holes, and we now know that we have struck 
upon an abode of the pholas, a shellfish of very ancient 
fame. 
But hoAV are we able to procure a specimen ? A little 
patient quarrying with the hammer and chisel at the place 
of our first discovery might reward us ; but let us follow up 
the layers in the shelves, of which we will have a better 
chance. There, within a dozen steps from us, is what we 
want. A few good strokes with the hammer alone sunders 
about a superficial square foot of the rock, and in this piece 
we are fortunate in securing a number of splendid specimens, 
and breaking the stone into several sections, we lay open the 
wonderful creature to view. The lower half of the valves, 
we notice, is somewhat triangular in shape, and the top half 
is a very nice oval. These are bound together at the back 
by a ligament, or hinge, of an elastic nature, and they do 
not cover one half the milk-white body of the creature, 
which greatly protrudes in front and both ends. The 
pholas is mentioned by Pliny, and seems to have been a 
favourite on the tables of the epicure of his day. A belief 
existed amongst them that the creatures can secrete a 
luminiferous fluid, which causes everything on which it falls 
to shine with a pale phosphorescence ; and those who eat the 
animals raw, in the dark, appear in a most awe-inspiring 
fashion to be breathing flames. 
It was also said that the same light-giving property 
accompanied the creatures in their living state down in their 
dark abodes in the rocks below ; but during many months 
of patient watching of their habits in my tank, 1 could never 
detect a single spark of phosphorescence emitted from them 
