pends wholly on the horfe for its prefervation and continuance. The flies we are speaking of, like thofe of all other fpecies, receive their firft life and growth in the form of worms, -but thefe are worms that can be produced and nourished only in the intestines of a horse. It is there alone they can enjoy the proper temperature of heat, and receive the nourishment neceffary for them.

Befides the long, and fometimes very long worms which have been obferved in the bodies of horses, there have been alfo fhort ones.[By thefe are to be understood what we call Botts.]

All authors, both ancient and modern, who have treated of the diseases of horses, have taken notice of these worms, but M. Val lifnieri is, I believe, the firft who has traced them to the last stage of their transformation, and has feen them change into a hairy kind of Яly like the drone.

The flies from which thefe botts are produced inhabit the country, and do not come near houses, at leaft not near thofe of great towns; and therefore horfes are never liable to have these worms (i. e. botts) in their bodies; if they have have been kept in the houfe, efpecially in a town, during the fummer and autumn.

It is in the former of these seafons, and perhaps too in the beginning of the latter, that the females of thefe flies apply themfelves to the anus of horses, and endeavour to gain admittance, in order there to depofit their eggs, or perhaps their worms.

The precife inftant of their entrance will scarce admit of an eyewitnefs, but by the meereft chance;

yet M. Vallifnieri fays, that Dr. Gafpari had attained this very uncommon fight. The doctor (he tells us) was one day looking at his mares in the field, and from being very quiet he obferved, that on a fudden they became very reftlefs, and ran about in great agita tion, prancing, plunging, and kicking, with violent motions of their tails. He concluded, that thefe extraordinary effects were produced by fome fly buzzing a bout them, and endeavouring to fettle upon the anus of one of them; but the fly not being able to fucceed, he obferved it to go off with lefs noife than before, towards a mare that was feeding at a distance from the reft; and now the fly taking a more effectual me thod to obtain its defign, paffed under the tail of the mare, and fo made its way to the anus.

Here at first it occafioned only an itching, by which the inteftine was protruded with an increased aperture of the anus; the fly taking the advantage of this penetrated further, and fecured itself in the fold of the inteftine;-this effected, it was in a fituation proper for laying its eggs. Soon after this the mare became very violent, running about, prancing, and kicking, and throwing herself on the ground; in fhort was not quiet, nor returned to feeding, till after a quarter of an hour.

The fly then we fee can find means of depofiting its eggs, or perhaps its worms (i. e. botts) in the fundament of the horfe, which, once effected, it has done all that is neceffary for them.

If these bott worms are not hatched when firft depofited in the horse, but are then only eggs

it will not be long before it hap pens, from the nutritive heat they there receive.' or

Thefe bott worms, foon make their way into the intestines of the horle; they occupy fuch parts of this region, on, as are to them moft convenient; and fometimes (as we fhall fee prefently) they penetrate even to the ftomach all the hazard they appear to be expofed to, is that of being carried away from the places they have fixed on by the excrement, which may feem likely to drive all before it. But nature has provided for all things, and when we fhall have further defcribed thefe bott worms, it will be feen that they are able to maintain their fituation, and to remain in the body of the horfe as long as they please.

There is a time when thefe bott worms are of themselves defirous to leave this their habitation, it being no longer convenient to them after the purposes of their growth are anfwered. Their transformation to a fly must be performed out of the horse's body, and accordingly, when the time of their transformation draws near, they approach towards the anus of the horfe, and then leave him of their own accord, or with the excrement, with which they then fuffer themfelves to be carried along.

The figure of these bott worms affords at firft fight nothing remarkable, but they appear like many other worms of the firft clafs, to which they belong, that change into flies with two wings, and like the greatest part of the worms of that clafs, they are provided with a fort of fcaly claws, with which they draw themfelves forward.

There is a difference in colou obfervable between those that are taken by force from the intestine of the horse, and those which come away of their own accord, fome are greenish, fome yellowish, and others nearly brown; thefe laft are nearest to, and the greenifh ones the fartheft from the time of their transformation.

If M. Vallifnieri and myself have rightly obferved the pofition of their claws, fome of them differ from each other in this respect, but are perfectly fimilar in every other particular, and which change into flies fo nearly alike, that I am convinced, they are of the fame kind and origin.,

However this be, the bott worms, which are the subject of our prefent purfuit, have two unequal claws; and fince I have been acquainted with the nature and ufe of them, I have had no difficulty to conceive, how they may ftill remain in the intestines of the horfe, in oppofition to all efforts of the excrement to force them out-one of them, that I was handling and examining, faftened upon my finger in fuch a manner, that I found great difficulty to difengage myself. Thefe claws are a fort of anchor, differently difpofed from thofe of common anchors, but contrived to produce ..the fame effect.

1

decount of a marine production of a very ambiguous nature, from the Philofophical Transactions for the year 1762

Ns the month of June, 1759, the fquadron defined against Quebec arrived in the river St. Laurence, when being in the lati tude 49. 50. north, and about ten leagues to the eastward of Anticofti (an island in the mouth of the river) we founded, and ftruck ground in 42 fathoms; the foundings white fand and black fpecks. Having, at the fame time, thrown over a fifhing-line, the hook was found ftrongly attached at the bottom; and, after fome efforts, brought up a piece of rock into the furface of which was inferted a ftrong tendinous fubftance, of a light brown colour, in length about feven inches; it was round, and nearly of the thickness of a common goofe-quill; the other end formed a fack, or bag, of the fize and fhape of a pigeon's egg.

The whole of this fubftance was elaftic; and, upon preffing the bag, I plainly difcovered a contained fubftance, and imagined, that it was attended with motion, Thefe, Sir, are all the particulars I have got to offer upon this unknown fubject, whether animal, zoophite, or fubmarine plant, I leave to your determination.'

Priapus; give us leave, therefore, to name it Priapus pendunculo fili.. formi corpore ovato. The body was oval, and in fize between a pigeon and pullet's egg, fmooth, membranous, and of a filver afh colour. What appeared to be the mouth was fituated a little below the apex, and was quadrivalvular, in the form of a (+) crofs. The anus was on the fame fide, a little above the bafe, or infertion of the ftalk, and alfo quadrivalvular. To: wards the apertures of the mouth and anus, the body felt more callous. From this body iffued a peduncle, or talk, of ten inches in length, the extreme end of which was fixed to a piece of rock. This talk was of a light brown colour, about the thickness of a large hen's quill, round, hollow, rough, and of a membranous, leather-like fubftance.

When the body was opened, the internal coat appeared to be compofed of reticular fibres. The interior orifice of the mouth was furrounded by a radiated fubftance, about the fize of a filver penny, thicker, and more callous than the coats of any other part. The internal aperture of the anus was compofed of fibres interwoven with one another. From the apex to the base on each fide defcended obliquely, and winding, a smooth folid body, in width about one fifth part of an inch, part of which feparated in the examining. We cannot give a clearer idea of this body, than by faying, that it had greatly the appearance (except in fize) of one of the fmalleft inteftines, and was attached to the interior furface of the main body, much in the way as they are to the mefentery.

Remarks

Remarks upon fome obfervations made by Henry More, Efq; on the the tides in the ftraits of Gibral

tar.

[We do not infert Mr. More's obobfervations, because they are fufficiently implied in theje remarks upon them.]

THE

HERE appears in the Philof. Tranf. Mr. More's obfervations on the tides in the ftraits of Gibraltar, which has fo long puzzled the ingenious the which, if they were new to him, are real ly ingenious, and the more fo as being generally true; and if they are likewife new to the royal fociety, fome further remarks may not be amifs.

I can fay of my own knowledge, that, forty years paft, there was nothing new in this to feamen. The notion of vapour, and undercurrent, we always efteemed unphilofophical, and were certain it was mere whim; and the experiment of letting down a bucket, mentioned by Mr. More, was really no experiment, nor any way proves an under-current.

That there are tides on both the Barbary and Spanish coafts is certainly true; and by knowing the courfe of those tides, a fhip may at any time, when the winds are contrary and moderate, beat up into the Mediterranean against a a Levant, or the ocean from Gibraltar, when the wind is wefterly; but it feems ftrange that the fame perfon, who informs us of this, could not inform us what is the courfe of thofe tides, though by his own account he went through the experiment; having, as he fays, at the finishing of the tide on

the Spanish coaft, flood over to the Barbary coaft, where he found the tide for him, and carried him clear off the capes; in which cafe a little reflection would have ascertained the true courfe of the tides on both fhores, and need not any conjectures about tides, half tides, &c. it being notoriously true, that the tides are as regular on both the Spanish and Barbary shores, as in the Thames or Medway, and which, until the appearance of Mr. More's obfervations, I never conceived to be a mystery; and if it has been fo to the royal fociety, I fhall here, from fome years experience, give an ample explanation.

The tide on the Spanish fhore, at full and change of the moon, makes high water at Gibraltar at three o'clock.

The tide on the Barbary shore, at the fame time of the moon, makes high water in Tangier bay likewife at three o'clock.

is

The flood on the Spanish fhore into the Mediterranean; the flood on the Barbary fhore is into the Atlantic; fo that when with a wefterly wind a fhip leaves Gib raltar, fhe takes the advantage of the ebb on the Spanish coaft, and when the has beat up within a certain diftance of Tariffa, and the tide near ended, the ftands over for the coaft of Barbary, and then by the aid of the flood tide, may, if a tolerable failing fhip, attain Tangier bay, and the next tide get clear of the capes.

I do not fpeak this from conjecture, but experience; and had I dreamed that it had been a mystery now, which forty years paft was known to many, I should have thought it my duty to have mentioned it before.