SIR,

IN your 133rd number, for May last, page 410, it is stated as a curious fact in the natural history of the common eel, that a number, consisting of old and young, had beep discovered in a subterranean pool at the bottom of an old quarry, which had been filled up and its surface ploughed and cropped more than twelve years. The information was evidently intended to convey an opinion that the young eels, found in the pool, had actually been bred therein; and, could that circumstance have been unequivocally established, it would have been a new and interesting fact in the natural history of the animal. I, however, imagine, that a strict investigation of all the circumstances of the case, made on the spot, would have shown that the young eels had recently found their way into the pool, in the same manner as the old ones had formerly done; that is, by some aqueous communication, however temporary or trivial, with any, the most insignificant, adjoining brook or rill. It is certainly difficult to conceive how even a subterranean pool can preserve its water for more than a dozen years, perfectly isolated from all other water; and if any communication, however temporary, and however minute, had existed, the circumstance of finding the old and young eels together, would be only an ordinary occurrence. Indeed, I find no difficulty in pronouncing, that the case spoken of furnishes no satisfactory evidence of the fact it was intended to establish.

I believe there is no animal, if we except man himself, that is so disseminated over every climate and country in the globe, as the common eel. In almost every instance where fresh water either flows, or is permanently stationary, the eel is an

inhabitant; and throughout every part of our own country, not only every river and brook, but also every piece of stationary water, from the largest lakes down to many of our common wells, are found, in the proper season, to abound with eels; and yet both the place and the manner of their propagation still remain a question in zoology. There are also, many other facts in their history, that are very obscure; and it would be an interesting addition to the researches of the British zoologist to have the whole satisfactorily cleared up. In furtherance of this object, and to narrow the field of inquiry, I here offer, Mr. Editor, such facts as have fallen within my own observation, of the natural habitudes of the eel. They are chiefly intended to induce some of your intelligent readers, whose situation furnishes them with better sources of information to communicate what they can learn on the subject.

In all inland waters, eels abound without number in summer, but disappear in winter. This disappearance has been variously accounted for, and it has been very generally imagined that a large proportion hibernate, by bedding themselves in mud; a notion which, I believe, is quite as visionary as the hibernation of swallows under water. Were eels ever in the habit of penetrating into mud, they would naturally enough shelter themselves therein, when exposed to imminent danger, and no other mode of escape presented itself; but I have seen very many instances of muddy pools, purposely and speedily drained off, where multitudes of eels crawled over the light surface of the mud in all directions to escape, and without ever attempting to conceal themselves by penetrating into it. The full and clear eye of the eel,

also furnishes evidence that nature never intended that animal to be buried under mud.

The disappearance of eels, in rivers and brooks, may be well accounted for by their emigration to the sea. This emigration is called their running. It commences in autumn, when immense quantities pass down the streams. Great numbers take the advantage of descending with floods, but a large proportion pass down wards in the night, and only in the darkest and most tempestuous nights. Moonshine wholly suspends their progress; and even a temporary gleam of light, when the night is otherwise favourable, immediately interrupts their journey. This proves that their emigration is not a casual but a premeditated system in their existence: and it also displays their instinctive cunning; for, being an easy prey, when discovered, to otters, herons, and other nocturnal enemies, it is only in the darkest nights that they can travel in safety. During the period of their run, vast quantities are caught in bag-nets, set across the streams. There is reason to suspect that all the eels in rivers do not run for the sea, as, very early in the spring, large eels abound in rivers at such a distance inland, as renders it highly improbable that they can have ascended so far at so early a period; and, indeed, it is yet an unascertained fact, whether, of the vast multitude which unquestionably do pass downwards to the sea, any of them do again return and ascend to any distance up the streams. If, indecd, this retrograde emigration really existed to any extent, there are thousands of situations on our streams where it must have been every season perceived; and yet it has not only not been discovered, but the instances are frequent, where the obstacles, on many of our streams, render it impracticable, and where, nevertheless, large eels are found above these obstacles as early, and as abundantly as below them. The probability, therefore, is, that

few or none of the vast numbers which descend the streams, ever again return; and then, as they are never discovered in the sea itself, the question of what ultimately becomes of them, is just as obscure as that of their generation.

There are many lakes, and multitudes of pools, abounding with eels, and from which they cannot run on account of the insufficiency of the outlets; and in these situations, the eels, most certainly, continue during the period of their existence. There, however, they regularly disappear in winter, and the manner of their hibernating is entirely unknown. But as no species of animal, with which we are acquainted, ever does breed during the time of its hibernation (the thing, indeed, seeming physically impossible) and as eels, in these confined situations, are taken at all other times, without any vestige of propagation being discovered amongst them, the inference seems conclusive, that eels never do, under any circumstance, breed in fresh water. Were it, indeed, practicable in a single instance, it would be equally so in thousands of others, where the circumstances are so similar; and it would be passing strange if a solitary quarry pit, which had been excluded for a dozen years even from day light, were to discover to us an occurrence which is never displayed in our multitudinous open pools, where the same animals are equally restricted from escape.

In contradistinction to the vast emigration of old eels down the streams in autumn, an immensely greater migration of young ones commences up the streams in spring and summer. Their size varies between the smallest and the largest darning needle. They are called elvers, and abound in some of our large rivers, to an inconceivable extent. In some places, bushels of them are taken with baskets fixed on to the ends of poles, and drawn swiftly through the water. Their progress is always along the banks, and

numerous portions pass up into all the lateral streams. The smallest brook and the minutest rill that can run receive their proportion; and it is solely in this way that every piece of water, however or wherever it may be situated, receives the eels that are found in it. The smallest possible trickling of water from any pool to the nearest brook, is sufficient to enable these little indefatigable animals to wind their way up to the source. The instinct, indeed, which impels them upwards against all moving water seems incessant and irresistible; it surmounts every difficulty, and perseveres successfully against every obstacle, however imperious. During the slow state of streams in the early part of summer, they may be found at weirs, inilldams, cascades, and other elevations across the streams, ascending, by the margin of the water, perpendicular walls many feet in height, where the least crevice in the stone, or patch of moss, affords them a hold; and they will even find their way over vertical dry boards, by adroitly employing their glutinous exteriour. I have taken them in handfuls from patches of wet moss against erect walls, completely out of the water, and where the height and distance to be surmounted would require the persevering efforts of many days. In very small, pellucid brooks, adjacent to rivers where they abound, they may be seen wriggling up the little streams, in endless succession, for weeks together. Great numbers doubtless perish by ascending the temporary rills produced from rain, and by reaching spring heads, and situations where the water is insufficient for their growth and support. But in this, as in every other instance, provident nature has guarded against all such casual expenditure, by the superabundance of the production.

In the larger rivers, communicating with the sea, although the elvers appear to advance in vast bodies, I do not imagine their migration,

either in its commencement or progress, is made in concerted shoals; it seeming more probable that the number found together is accidental, and arises from the continual supply sent off from the quarter where they originate. This is confirmed in the small streams, where each individual is seen making its way by its own solitary efforts.

In summer, all the large eels in rivers and brooks, conceal themselves during the day under large stones and roots of trees, and in the crevices of rocks and walls, and even in earth-holes of the banks; and in these situations, they obtain a large proportion of their food, being always on the watch to seize small fish, or other prey that the stream or acci、 dent throws into their concealment; and I think it is much more probable that the eels which do not find their way down to the sea, pass the winter in similar situations, rather than bedded in mud, or in any other of the fanciful modes which have been assigned them.

Such are a few of the principal facts in the natural history of the common eel, a creature which every where surrounds us, in the greatest abundance, and yet its origin, and final disposal, are equally unknown. That it never does breed in fresh water, seems to be a fact well established; and the periodical descent of the old ones to the sea, and ascent of the young ones from thence, strongly evince that the scene of their propagation is in the sea itself, or very near to the mouths of rivers, and that it is there that inquiries on the subject should be prosecuted.

The growth of the eel, like that of most other fish of prey, does not appear limited to any determinate natural bulk, but to be governed only by the age and abundance of food. In this country they are indiscriminately of every size, up to eight or nine pounds weight. They have ge nerally been supposed viviparous: but the immense abundance of the young certainly bespeaks an ovipasf