AMONG the amusements of the sea-shore there is, perhaps, none so capable of yielding a varied pleasure to a person whose taste for Natural History is awakened, as dredging, where it can be carried on under favourable circumstances. It is not on every coast that dredging can be practised. On some, the surf is habitually too great to admit of boating, as on parts of the west of Ireland, where a rock-bound shore presents no harbours for boats, and the fishermen are destitute of any other than canvas canoes, totally unfit for the purposes of dredging. On these coasts the broad waves of the Atlantic, continually rolling in, keep up a troubled water in which the pursuits of the deep-sea naturalist

NATURALIST'S DREDGE.

117

can rarely be carried on. In other places, a rocky, or as it is technically called, a foul bottom, presents insuperable obstacles to the use of a dredge. It is only, therefore, in certain favoured localities that dredging can be resorted to as an amusement by the frequenter of the sea-shore. Land-locked bays, and harbours where a quiet water flows over a smooth or a shingly bottom, or lies on oyster or scallop beds; these are the favourite ground for the amateur dredger, and these will generally yield him abundance of sport for the length of a summer day.

Those who have never seen a dredge may wish to have one described. There are several varieties of the instrument. The com

mon one, with a single scraper, being in use among the fishermen on most parts of the coast, needs no de

scription, as it may

generally be had by

inquiring of your

boatman; but there

is another kind, to

which the name of

Naturalist's Dredge

NATURALIST'S DREDGE.

may be given, which possesses some advantages over the common dredge, and which can only be had by ordering it specially of a blacksmith. This kind was first recommended many years ago by Mr. Robert Ball, the

118

NATURALIST'S DREDGE.

well-known zoologist, and its value has been largely tested, especially in deep-sea dredging. It is an iron. rectangular frame, made with a scraper at each side, and having a bag attached to it in the usual manner. Its handles are moveable, being connected by eyelet holes with the bars of the frame below, and united, where they join above, by a ring and screw, so that when you wish to pack up the dredge, the handles, on the ring being unscrewed, fold up, and the whole fits into a small compass. This compactness is one advantage of this kind of dredge, as it renders it much more easy of carriage. But its great value lies in the double scraper, which makes it a matter of no consequence on which side the instrument is thrown down. It cannot be reversed. The top and bottom being alike, it is a matter of indifference which shall scrape the ground. In working with a common dredge, if the instrument be not carefully thrown down it is very liable to overset, and, unless it fall with the scraper in the proper position, it will not collect anything. The Naturalist's dredge cannot overset, because either side scrapes equally well. And this, when dredging in deep water, is a quality of the greatest value.

We will suppose the dredger afloat, on a fine day and in a favourable locality, furnished with his dredge, and with some collecting boxes and bottles, and a sieve to sort the smaller animals from the mud and silt. When the water is clear and not very deep, the aspect of the bottom, as the boat glides quietly over it, often affords a charming submarine picture, as well as reveals the places where the dredge may be most profitably thrown down. The larger sea-weeds, seen like a forest waving

DRAGGING FOR SEA-WEEDS.

119

in the clear water below you, generally mark the posi tion of rocks, and forbid the use of the dredge; but often the treasures of such ground may be rifled by using another instrument, called a drag, which can sometimes be employed on foul ground with much effect. This instrument consists of a series

of barbed hooks attached to a transverse bar and connected with a rope. It ought to weigh at least five or six pounds. This is to be dragged along among the leaves of the large sea-weeds, care

DRAG.

being taken, when the ground is very foul, not to allow it to fall into holes among the rocks, in which it would be liable to be caught. By suffering it to drag among the sea-weeds, some of these will be detached, and being caught by the hooks, may readily be hauled up; and such leaves often afford a rich harvest. The stems and fronds of the great oarweed are very generally clothed with smaller algæ, of which many species are to be obtained only on them. The beautiful Ptilota plumosa is altogether confined to the stems of Laminaria digitata, and these stems are also the favourite habitat of many other of the more delicate Floridea. Callithamnion Pluma, a minute but very beautiful species, forms upon them a covering resembling fine crimson velvet ; Delesseria ruscifolia; Rhodymenia palmetta, and Polysiphonia urceolata, are also commonly to be met with. The number of marine animals attached to these weeds is also considerable. Several of the Sertularian and

120

PARASITES ON LAMINARIÆ.

other zoophytes; various and beautiful kinds of Botryllus and of other compound Ascidians, as well as several of the gasteropodous molluscs, may be collected either on the broad leaves or among the roots of the Laminaria. Two kinds of Patella (P. pellucida and P. lævis), both remarkable for longitudinal streaks of iridescent colours on an olive shell, may be found feeding on the Laminariæ; the former generally upon the broad leaves, the latter among the fibres of the root, or upon the fleshy stem, and very frequently within the bulb of L. bulbosa. To the labours of these little molluscs may, indeed, be partly attributed the annual destruction of these gigantic Algæ. Eating into the lower part of the stems, and destroying the branches of the roots, they so far weaken the base, that it becomes unable to support the weight of the frond; and thus the plant is detached and driven on shore by the waves.

At depths beyond which the Laminariæ cease to vegetate, that is, from about four to ten fathoms, -the bottom of the sea is frequently covered with a vegetation of a very different character, which, indeed, will scarcely be taken, by a hasty observer, to belong to the vegetable kingdom at all. In speaking of Corallines in a former chapter, I alluded to a kindred race of vegetables, called Nullipores or Melobesiæ, of a stony character, whose outward coating and much of whose interior fabric, are composed of carbonate of lime, secreted in their cells, and forming an organized portion of their bodies. Vegetables of this class bear a striking resemblance to the skeletons of some of the larger calcareous zoophytes, especially to some of the Celleporæ ;