102 ANIMAL LIFE ON THE 
molluscs which does the work of the liver, and is far too soft 
and pulpy for the seat of a stone and water ejecting valve. 
Wearied of speculation and conjecture, we turn another 
way. With the upper sides of the foot well separated from 
the surrounding mantle, we have a favourable opportunity 
of turning our eye further inward. There, encircling the 
shoulders and hanging from the base of the syphon tube, we 
see a number of very thin fringes, something like the 
texture of those of the scallop, and these are evidently 
armed with numerous and powerful cilia. Again we notice 
a long tongue-like instrument. There are two of these, one 
on each side, of the same material, coming down the cavity 
with a sweep, and returning again. On steady and close 
observation, we notice, attached to the tips of this tongue, 
the very threads spoken of by Harper. Like the line 
thrown by the deft hand of the rod fisher, the thread is cast 
to the base of the foot, then quickly withdrawn straight up 
out of sight. We have thus gained two important points 
in the field of our research, but a third is needed to 
complete the chain. Casting our eye along the base of the 
valves, we here observe the surface of the foot gathered 
up like a thin ring encircling the round of the shells. 
Taking the creature up to the surface of our glass of 
water, we press the foot with our finger until it withdraws 
pretty well within, and then replace it to watch the result. 
* Since the above observations were penned, from a further tracing of the bed 
of this instrument, I find that it occupies a chamber in the heart of the foot, lined 
with soft tissuey lining, and at its base is much larger than t^at of the instrument. 
This chamber, I am of opinion, is a store-house for the gummy liquid which makes 
the threads spoken of by Harper, and the instrument itself is the creature's, 
spinning distaff. In support of this, I may mention that the point of the instru- 
ment has a half turn bend which fits into a sort of double-edged screw worm, 
composed of a tough scaley substance, very much harder than the surrounding 
material, and immediately behind the bend, and adhering to it, I noticed a fixed 
watery-coloured material through which the liquid threads seem to be pressed ta 
the outside for use. 
