Glimpses of Ocean Life 10

Glimpses of Ocean Life 10

For those of my readers who may prefer verse to prose, I here append a

poetical version of this fable--equally pretty, but, let me add in a

whisper, equally opposed to fact, at least in its principal details:--

 

'In clouded depths below, the Pinna hides,

And through the silent paths obscurely glides;

A stupid wretch, and void of thoughtful care,

He forms no bait, nor lays no tempting snare;

But the dull sluggard boasts a _crab_ his friend,

Whose busy eyes the coming prey attend.

One room contains them, and the partners dwell

Beneath the convex of one sloping shell:

Deep in the watery vast the comrades rove,

And mutual interest binds their constant love;

That wiser friend the lucky juncture tells,

When in the circuit of his gaping shells

Fish wandering enters; then the bearded guide

Warns the dull mate, and pricks his tender side.

He knows the hint, nor at the treatment grieves,

But hugs the advantage, and the pain forgives:

His closing shell the Pinna sudden joins,

And 'twixt the pressing sides his prey confines.

Thus fed by mutual aid, the friendly pair

Divide their gains, and all their plunder share.'

 

There is one singular feature in the Crustacea which it may prove

interesting to dwell a little upon. I allude to their power of living

apparently without food, or at least without any other sustenance

than is afforded by the animalculæ contained in the water in which

they dwell. One accurate observer states that he kept a Cray-fish for

a period of two years, during which time the only food the animal

received was a few worms,--not more than fifty altogether. This

statement I have often had ample means of verifying. Yet, on the other

hand, strange to say, the crab is always on the hunt after tit-bits;

and nothing seems to give him greater delight than a good morning meal,

in the shape of a newly opened Mussel, Cockle, and above all--a Pholas.

Let a youthful crustacean cast its shell, and rest assured, unless its

companions have had their appetites appeased, they will endeavour to

fall upon and devour the defenceless animal. This, to my chagrin and

annoyance, I have known to occur repeatedly. When nothing else can be

procured, not only the Lobster Crabs, but any Brachyurous Decapods

who may be at hand, will set to work, and industriously pick off and

eat the Acorn-Barnacles attached to any object within reach. These

facts show that the asceticism of the crab is not voluntary, and that

when opportunity occurs, he is as fond of a good dinner as are animals

possessed of a higher degree of organization.

 

It will be gratifying if other observers are able to verify the

circumstance which I shall allude to hereafter, and which would seem

to show that the _exuviation_ of crustacea is expedited by affording

specimens an unlimited supply of food.

 

'The organs for pursuing, seizing, tearing, and comminuting the food of

the Brachyurous Decapods,' says Professor Bell, 'are carried to a high

degree of development; ... these appendages consist of six pairs, of

which some are actual organs of mastication, as the mandibles or the

true jaws, the foot jaws or pedipalps, generally serving to keep the

food in contact with the former, whilst it is being broken up by them.

 

'The buccal orifice in the Brachyura occupies the interior face of

the cephalic division of the body, and is bounded anteriorly by a

crustaceous lamina of determinate form, which has been termed the upper

lip, and posteriorly by another, termed the lower lip. The mandibles

occupy the sides of the opening. After these, and external to them,

are the first, and then the second pair of true jaws, followed by the

three pairs of pedipalps or foot jaws, the last of which, when at rest,

close the mouth, and include the whole of the preceding ones. In the

Macroura the pedipalps are very different in their forms, and have the

aspect of very simple feet.

 

'The means of comminuting the food are not restricted to the

complicated machinery above referred to, for the stomach itself

contains a very remarkable apparatus, consisting of several hard

calcareous pieces, which may be termed _gastric teeth_. They are

attached to horny or calcareous levers, fixed in the parietes of

the stomach; they are moved by a complicated system of muscles, and

are admirably adapted to complete the thorough breaking-down of the

aliment, which had already been to a considerable extent affected by

the buccal appendages. These gastric teeth may be readily seen and

examined in the larger species of Decapoda, as in the large eatable

crab and the lobster; and it will be readily perceived how perfectly

the different pieces are made to act upon each other, and to grind the

food interposed between them.'

 

Having been on a certain day at the sea-side collecting, I was amused

to observe the movements of two ragged little urchins, who approached

near to where I stood, bottle in hand, examining some beautiful

zoophytes by aid of a pocket lens. One of them had a short iron rod,

with which he very dexterously hooked out any unfortunate crab who

happened to have taken up its quarters in some crevice or beneath

a boulder. Having captured a specimen, it was handed over to his

companion, who quickly tied it to a string which he held in his hand.

 

I had seen many a rope of onions, but this was the first time I had

seen a rope of crabs. On inquiry, I learned that the boys had taken two

dozen animals in about two hours. When any of the green-bellied crabs

happened to be poked out, they were allowed to escape back again as

quickly as they pleased.

 

With poor _Cancer pagurus_ the case was different,--every specimen, as

soon as caught, being strung up, and doomed to 'death in the pot.'

 

The above, I need scarcely state, is not the usual manner of fishing

for crabs, the approved plan being to take them in what are termed

crab-pots, 'a sort of wicker-trap made, by preference, of the twigs of

the golden willow (_salex vitellina_), at least in many parts of the

coast, on account, as they say, of its great durability and toughness.

These pots are formed on the principle of a common wire mousetrap, but

with the entrance at the top; they are baited with pieces of fish,

generally of some otherwise useless kind, and these are fixed into the

pots by means of a skewer. The pots are sunk by stones attached to the

bottom, and the situation where they are dropped is indicated, and the

means of raising them provided, by a long line fixed to the creel, or

pot, having a piece of cork attached to the free end of the line; these

float the line, and at the same time serve to designate the owners

of the different pots--one, perhaps, having three corks near together

towards the extremity of the line, and two distant ones--another may

have one cork fastened crosswise, another fastened together, and so

on. It is, of course, for their mutual security that the fishermen

abstain from poaching on their neighbour's property; and hence we find

that stealing from each other's pots is a crime almost wholly unknown

amongst them.'

 

'The fishery for these crabs constitutes an important trade on many

parts of the coast. The numbers which are annually taken are immense;

and, as the occupation of procuring them is principally carried on

by persons who are past the more laborious and dangerous pursuits of

general fishing, it affords a means of subsistence to many a poor man

who, from age or infirmity, would be unable without it to keep himself

and his family from the workhouse.'[3]

 

[3] Bell's Brit. Crus.

 

 

 

 

CHAPTER V.

 

Hermit-Crabs.

 

 

'Finding on the shoar

Som handsome shell, whose native lord of late

Was dispossessed by the doom of Fate,

Therein he enters, and he takes possession

Of th' empty harbour, by the free concession

Of Nature's law--who goods that owner want,

Alwaies allots to the first occupant.'

 

DU BARTAS.

 

 

 

 

[Illustration:

 

1 COMMON HERMIT-CRAB (_Pagurus bernhardus_) in shell of common Whelk

2 COMMON HERMIT-CRAB out of shell

3 SHIP BARNACLES]

 

 

 

 

V.

 

 

Twice in every twenty-four hours the waters of the ocean ebb and flow.

Twice only in each month, however, do the spring-tides occur. For there

are few dangers that the ardent student of nature would not encounter.

Lord Bacon tells of a certain bishop who used to bathe regularly twice

every day, and on being asked why he bathed thus often, answered,

'Because I cannot conveniently bathe _three_ times.' The zoologist,

like the 'right reverend father' alluded to, would willingly undergo

what appears to others much hardship and trouble, not only once or

twice, but even three times daily, in pursuit of his favourite studies,

did Nature but offer the kind convenience.

 

On these occasions the zoologist can pursue his researches at the

shore, at a distance beyond the usual tidal line. Numerous boulders and

rock-pools, during many days covered by the sea, being then laid bare

and exposed to his eager, searching hands and eyes, he is frequently

able to discover many rare objects, or, at least, common ones

revelling in almost giant-like proportions, and wonderful profusion.

 

The Soldier or Hermit-Crabs (to an account of whom we intend to devote

this chapter), offer a most remarkable proof of this. Occupying the

centre of a rocky excavation, I have repeatedly found several dozen

of these comical creatures, each inhabiting the cast-off shell of a

defunct Whelk (_Buccinum undatum_), which measured not less than five

or six inches in length. To my surprise these aldermanic crustaceans

possessed no companions of a smaller growth; while at a few yards

nearer shore, as many shells would be found congregated together as in

the more distant pool,--the largest, however, being no bigger than a

damson, while the smallest might be compared to an infantile pea, or

cherry-stone.

 

I cannot explain this appearance otherwise, than by supposing that

the _Anomoura_ become prouder, or, it may be, more cunning, as they

grow older, and, having arrived at their full development, they

fit themselves with their final suit; thereafter, in a spirit of

aristocratic exclusiveness, they retire to fashionable subaqueous

residences, distant as far as possible from the homes of the

_canaille_, who inhabit the common, littoral boundaries of the shore.