I was 'on thorns' until next day, so that I might by watching solve the mystery. A third Pholas was flung into the den. The fishes, eager as usual, instantly attacked and pulled the mollusc to pieces. After a while the crab began to move about to and fro, evidently very restless, and anxious for my departure. I did retire, but only to such distance as would allow me a distinct view of his movements. In a few moments he stepped out mincingly on the tips of his toes, and crossed the tank to the spot where the poor Pholas lay, like some fine beau in Queen Anne's reign tripping jauntily down the Mall, or across St. James' Park, to feed the ducks in Rosamond's Pond.
The Blennies darted off at his approach. He then seated himself before the mangled corpse, and scraped at it vigorously, manifestly searching for some coveted treasure. Shortly after, perceiving him clutch at something, I quickly approached and disturbed his movements—took up the Pholas, and to my surprise found, on drawing out an object that protruded from the foot of the animal, that I possessed the pearly and gelatinous cylinder, such as the crab had twice before devoured with such evident relish.[11]
It was plain then that the little rascal had become so dainty, that he 'turned up his nose,' or rather his 'pair of noses,' at what is vulgarly termed the 'first cut,' and condescended only upon the tit-bits, for his marine banquet. So his crabship, in order to save himself trouble, actually waited until the fishes had cut up the Pholas to a certain point, when he would rush forward and seize on his favourite fare.
Some of my readers will doubtless remember the anecdote of the crossing sweeper, whose idiosyncrasy led him to covet diurnally a mutton-chop situated in the middle of the loin. My Lady Pepys, or Mr. Saccharine, the great grocer, couldn't always procure the desired 'cut!' n'importe the knight of the besom met with no such disappointment.
This individual's place of business was luckily situated opposite to a noted butcher's shop, which circumstance easily enabled him to watch until, from the demands of sundry customers, the perspective of the loin, which lay temptingly upon the chopping block, had become adapted to his point of sight. He would then step in and meekly order a simple pound avoirdupois. With this bonne-bouche carefully packed in his pocket, he would again mount guard, and remain until night. At dusk of evening he shut up shop,—that is, he swept the dirt over the parallel path that he had all day kept scrupulously clean, and then marched off to enjoy his dinner at a fashionable hour, in private.
Are not these cases palpably alike? Passing by certain details, were not the pawkiness and cunning of the epicurean beggar fully equalled by our diminutive friend, C. mænas?
'But,' you ask, 'what then was the opal stick?' Ay, there's the rub, for even the greatest naturalists cannot positively agree as to the use and purpose of this mysterious organ. Yet it is to be found (as we have seen) in the foot of the Pholas, in the Mussel, the Cockle; and, in fact, it occurs in almost all bivalves both great and small. It is termed the 'hyaline cylindrical stylet,' and is very lucidly and scientifically described as 'an elastic spring to work the corneous plate or attritor, and by the muscular action of the foot and body, to divide and comminute the food, and especially the minute crustaceous and testaceous alimentary matters received into the stomachial cavity. It appears then that this appendage acts as a gizzard, and the bivalve mollusca are thus supplied with a masticatory apparatus very analogous to the gizzards of some of the gasteropoda.'
Now, the simple fact that I have stated above, of the hyaline stylet being found in the foot, and not in the stomach, at once proves that it cannot possibly act as a gizzard to the Pholas, or any other bivalve in which it is known to exist.
In the succeeding chapter I shall endeavour, from personal observation, to shed a slender ray of light upon the function of the stylet.