Page images

serves, has been very improperly applied to this kind of animals; for it is certain that not a single species of them is possessed of that stinging quality like a nettle, which the ancients ascribed to them, and that only their tentacula feel rough and clammy when touched with the finger. Even this roughness is not perceptible, but when the animal attempts to lay hold of the finger: it then throws out of the whole surface of the feeler a number of extremely minute suckers, which sticking fast to the small protuberances of the skin, produce the sensation of a roughness, which is so far from being painful, that it even cannot be called disagreeable.

The genus which these sea-nettles belong to is that of the hydra of Linneus, commonly called the polype. This will appear from the following characters: from the gelatinous substance, of which this whole tribe of animals consists; from their having only one opening in their bodies, which gives a passage to the food as well as to the excrements of the animal; and from a set of feelers, which surround this opening, and serve for claws to catch their prey and convey it to their mouths. As the sea-nettles agree perfectly in those general characters with the hydra, so do they also answer to many of its less essential, or merely accidental qualities: they live for instance constantly in the water, in which they never swim, but always adhere to some fixed body in it; and when they change their place, most of them crawl along so very slowly, that their progressive motions cannot be perceived with the eye. To this may be added, that they likewise bring forth their young ones alive, and that they grow again after considerable parts of their bodies have been cut off: all which proves still further, that these animal flowers, or sea-nettles, are of the same nature, have the same characters, and do consequently belong to the same genus with the hydra. The polypes in general may be divided into 2 classes, the one containing those polypes, that cannot conceal their feelers, though ever so much irritated; and the other, those that on the least irritation contract themselves, draw in their feelers, and frequently hide them under a membranaceous cover made for that purpose. The first class, on account of the small number of species belonging to it, needs no subdivisions; but to distinguish properly the several sorts of the 2d class, it is necessary to divide it according to the various positions of the feelers, which are inserted either in the membranaceous cover itself, or into a flowerlike production of the body, or lastly, in the very top part, or the disk of the polype: hence arise the three following subdivisions of the 2d class: 1. Hydra calyciflora. 2. Hydra corolliflora; and lastly, Hydra disciflora.

The first class consists but of a single sort, whose specifical character may be thus expressed:

Hydra tentaculis denudatis, numerosissimis; corpore longitudinaliter sulcato.* The body of this polype is of a light chestnut colour, and feels perfectly smooth,

though it be lengthways sulcated by a number of sulci, that are frequently divided into 3 smaller ones, and are continued into the dentated margin, that surrounds the upper periphery of the body, just beneath the insertion of the feelers. These feelers, rising from the disk of the polype, are, according to the age of the animal, between 120 and 200 in number; they exceed the body when expanded by more than an inch in length, and are of a beautiful sea-green colour, except toward their extremities, which are coloured with a lively red, like that of the rose. The disk is of the same brown colour with the rest of the body, and contains in its centre the mouth of the animal, which is an aperture of various shape and diameter. The two varieties of this species, which Dr. G. met with, differ but little from the already described animal. The feelers of the one, instead of being green, are throughout of a red colour, like that of mahogany wood. The other variety has pale ash-coloured feelers, marked with a small white line running along their back; its body is of the same chestnut colour with that of the first species; but the sulci are not divided, nor has it a dentated margin surrounding its upper periphery.

The polype belonging to the 2d class, concealing their feelers when irritated,, are the following: Hydra calyciflora, tentaculis retractilibus variegatis, corpore verrucuso.+

From its small basis rises a cylindric stalk, which supports the roundish body of the animal, whence afterwards the calyx, being a continued membrane of the body, draws its origin. The stalk, or the pendunculus of the polype is quite smooth, and its colour inclines towards carnation. The outside of the calyx, and the body of this animal, are marked with a number of small white protuberances, resembling warts, to which fragments of shells, sand-grains, &c. adhere, and hide the beautiful colour of these parts, which, from that of carnation, is insensibly changed towards the border of the calyx, first into purple, then violet, and at last into a dark brown. The inside of the calyx is covered with the feelers, that grow in several ranges upon it: they differ considerably in length; those that are near the edge of the calyx being but small papillæ, in proportion to those that surround the disk, or the central part of the body. They are almost transparent; and some of them are of a pale ash colour, with brown spots; others, on the contrary, are of a chestnut colour, marked with white spots. The disk is formed like a star, which, according to the figure that is traced out by the innermost row of the feelers, consists of many angles. The colour of this part of the body is a beautiful mixture of brown, yellow, ash-colour, and white, which together form variegated rays, that from the cen

This is the Actinia Cereus of Ellis.

This is the Actinia Bellis of Ellis,

tre, or the mouth of the animal, are spread over the whole surface of the disk. This polype contracting itself, changes its body into an irregular hemisphere, which is so covered with the several extraneous bodies that stick to it, that it is extremely difficult to know the animal in this state, and to discern it from the rubbish that commonly surrounds it.

These animals are frequently found in the pools about Mount's-Bay. It is rare to meet with a single one in a place, there being most commonly 4 or 5 of them living so near together in the same fissure of the rock, which they constantly inhabit, that their expanded calyces form a row of flowers like bodies, that seem to grow upon the cliffs under water.

The 3d species, is the Hydra corolliflora, tentaculis retractilibus frondosis.* This animal, in its contracted state has more the appearance of a caterpillar than of a polype. Its body is covered with a dusky white skin, in which a large opening appears at the thicker extremnity of the body, and at the opposite end of it are 5 small denticles, that surround a cavity placed in their middle. The surface of this cylindrical body is marked with 6 double rows of perforated knots, which the animal can transform into as many legs, if occasion requires, by extending each tuberculum into a small transparent cylinder, whose extremity, like that of the suckers of the star-fish, sticks fast to every thing which the animal gets hold of, and consequently serves it for an instrument, not only to fix its body with, but also to push it forward, by the help of many of these suckers that are formed of the several knots of different rows. The head of the polype coming out of the above-mentioned opening in the skin, is of an oval, and sometimes of an hemispherical figure, somewhat like the coralla of an asarum, but much larger in size. It is quite hollow within, and consists of a dark brown, yet almost transparent membrane, which, after having found the head, produces the feelers that surround the large aperture at the top of it. These feelers are 8 or 10 in number, and of the same substance and colour with the head; they are divided into several branches, to which, as well as to the principal stems, many clusters of very minute papillæ adhere, which make them exactly resemble small branches of trees covered with their leaves. These leaves, or papillæ, not only contribute to the beauty of the feelers, being of a pale yellow, mixed with a shining white like silver, but they also render the feelers more useful to the animal, in filling up the interstices between them, through which smaller insects else might pass, without being perceived by the animal, whose natural food they are. This polype seems to live at the bottom of the sea, distant from the land. Dr. G. met but once with it on the shore, between Penzance

* This animal is a species of Holothuria, and is the Holothuria pentactes of Linneus.

and Newland, where it is thrown up by the sea, inclosed in a large hollow root of the fucus palmatus.

The 3d species, is the hydra disciflora, tentaculis retractilibus subdiaphanis ; corpore cylindrico, miliaribus glandulis longitudinaliter striato. Its body when extended, is of a cylindrical figure, and constantly marked with some rows of small knots, or glandulæ, that are placed in straight lines from the top to the basis of this cylindrical stalk. Each row is composed of 3 files of glandulæ, of which the middle one is remarkably larger than the two others; their number is uncertain, yet he never met with less than 8 rows in an animal grown to its full age. The colour of the stock near its basis is a pale red, and the rest is of a yellow, mixed with a grey ash-colour. The glandulæ are almost of the same colour with the body, except those of the middle file of each row, which is white. Out of the top part, or the disk of the polype, grow the feelers, from 18 to 36 in number; they are of a half-transparent substance, and of a whitish colour, variegated only at the upper part of the feeler, like the back of some snakes, with several cross-lines, and brown spots of an irregular figure. The disk of this polype is always convex, and chiefly of an orange colour, except to. wards its periphery, which is marked with many dark brown spots, that surround the insertion of the feelers. At the least irritation, this animal contracts its body, and changes its cylindrical figure into a conoidal one. The fissures of the rocks in the sea are the only place where he met with this sort of polypes, which is not common on the coasts of Cornwall.

Of this species he found two varieties. The top parts of the one are in shape and colour much the same with those of the already described animal; the stalk only is of a deep green colour. The 2d variety has likewise a green stalk; but its feelers are not variegated, being throughout of a pale and transparent red colour. The animal flowers of Mr. Hughes, and the sea-nettle, with a shagreen skin of Mr. de Reaumur, may perhaps belong to this subdivision.

The last species of these polypes is the hydra disciflora, tentaculis retractilibus, extimo disci margine tuberculato.† The colour of its body is always red in the summer, but changes into dusky green, or brown, towards the latter end of autumn. The outside of it is quite smooth, some few animals of this sort excepted, which are marked, like the first species of this class, with small protuberances, to which several extraneous bodies likewise adhere. The feelers are constantly inserted into the disk of the polype, but they are of various colours, viz. red, blue, white, and sometimes even variegated. Between these feelers and the membranaceous cover of the animal, is a row of small hemispherical tu


This is the Actinia gemmacea of Ellis.

This is the Actinia mesembryanthemum of Ellis.

3 Y

bercula, which, though they vary in colour as much as the feelers, yet are constantly found to be placed on the edge or periphery of the disk, and consequently afford, together with the insertion of the feelers, a certain mark, by which this animal, so variable in its colour and shape, may be at all times known and distinguished from any other sort belonging to this tribe.

XIV. A Catalogue of the Fifty Plants from Chelsea Garden, presented to the Royal Society by the Company of Apothecaries, for the year 1760, &c. By John Wilmer, M.D. &c. p. 85.

This is the 39th presentation of this kind, completing to the number of 1950 different plants.

XV. An Account of the Cicuta,* recommended by Dr. Storke, By William Watson, M.D., F.R.S. p. 89.

Dr. W. observes that in a paper he had a short time before presented to the R.S. he had endeavoured to demonstrate that the Cicuta major which, since the publication of Dr. Storke's work at Vienna, had been used medicinally in England, was the plant intended by that gentleman; and not the Cicuta aquatica, as had. been suggested by some practitioners here. And Dr. Storke had removed every doubt, which could remain, by transmitting hither some leaves of the Cicuta major, or common hemlock, which grew at Vienna, and was of the same species with the plant so denominated here.

As Dr. Storke informs us, that, since the publication of his treatise, he has received letters from almost every part of Europe, confirming his good opinion of the virtues of the Cicuta, and as he is about to publish a 2d treatise on the same subject, containing still more extraordinary accounts of cures, brought about by administering that plant; there is no doubt therefore, but that endeavours will be made here, to confirm the truth of the doctor's assertions; more especially as some of the diseases in which Dr. Storke found the Cicuta attended with great success, are such as are of all others the most shocking to human nature, and have, by too long experience, been found to give way to no other means. Hence it is highly important to every one, more particularly to physicians, that the very plant directed by Dr. Storke be administered, and no other instead of it, either through inattention or want of knowledge; as judgment in the physician is of no real service, unless his prescriptions are faithfully prepared.

For these reasons, it may not be improper to inform those medical practitioners, who are not conversant in botany, and who may yet be desirous of trying the effects of the Cicuta, that at this time of the year there is another plant, growing

* Conium maculatum, Linn.

« PreviousContinue »