year at the Royal Academy up to some ten years ago. This is one of the most adequate examples of his elaborate style included in the present exhibition; we should have expected to find a fuller representation of so admired a miniaturist.

"Alice," by Wells, is an excellent miniature, showing the best attainment of the modern school; not unlike the works of Ross, but with greater force.

With this example we bid adieu to the exhibition; only regretting that we have been compelled to mention much fewer works, and those much more summarily, than the number, importance, and interest of the specimens displayed would demand. Our limits of space have compelled us to omit several names of sitters no less distinguished than Queen Henrietta Maria, Strafford, Hampden, Algernon Sidney, Henri IV., Sully, Condé, Turenne, Charles XII., Peter the Great, Maria Theresa, Frederick the Great, Lafayette, Talleyrand, Nelson, Marlborough, the elder Pitt, Clive, Warren Hastings, Washington, Montaigne, Lope de Vega, Ben Jonson, Milton, Corneille, Molière, Dryden, Newton, Pope, Swift, Voltaire, Kant, Scott, Byron, Raphael, Rubens, Wren, Handel, Reynolds, Flaxman, Wilkie, and Napoleon III.

REMARKS ON THE STRUCTURE AND ACTIONS OF
THE IRIS OF THE EYE IN SOME SPECIES
OF FISHES.

BY JONATHAN COUCH, F.L.S., ETC.

THE eyes of fishes differ in a remarkable degree from those of quadrupeds, birds, and reptiles, and especially in the want of a power by which the amount of light to be admitted may be regulated; and in consequence of what has been noticed of this, that portion of the eye of this class of animals which is termed the Iris has from the earliest times been considered as merely an immovable curtain or diaphragm, altogether incapable of contraction or dilation. In the second volume of Loudon's Magazine of Natural History, new series, Mr. Dalrymple remarks that he was never able to discover the slightest movement in this portion of the eye, and after many attentive observations on the cod family, the gurnards, and several others, I have arrived at the same conclusion. As regards the smooth blenny, or shanny, in particular, they have been subjected to the inquiry when at liberty in their native pools, where they were enticed by baits placed at different distances, to which they are never indifferent; but while looking at these

tempting objects, even at the distance of fourteen feet or nearer, no motion of the iris was perceptible; nor was there any change when the fish has been removed from the water into bright sunshine. The living young of the picked dogfish have also been taken from the body of the parent and exposed to the glare of a bright sunshine without any sensible effect on the iris; and when several examples of different kinds of fishes were examined, in order to ascertain whether some difference in the extent of this organ might be discerned in one or other of the several species, the result was that nothing further could be detected than might be looked for in the difference of size or other particulars of the same sort. But the result of our inquiry was somewhat different when the inquiry was extended to the species of the sharks and rays. But first, in the flat fishes, or Pleuronectidæ, the line of vision is not directed upward, as is often represented in the stuffed examples of museums and in many engravings; but the eyes are raised above the surface, and directed laterally, so that vision is protected from the glare of too much light, and the upper portion of the iris is so far bent downward as sometimes to serve the purpose of a partial screen; but still without the power of motion or contraction; while in the depressed section of cartilaginous fishes, or the rays and skates, this upper portion of the iris not only receives a new shape, but it is endued with a new property, which has an influence on the further modification of the eye itself, or the particular function of sight. The curtain, or veil, which hangs down from the upper portion of the iris is, in fact, a covering to the superior border of the pupil, for which it serves a use that has been particularly pointed out in our History of the Fishes of the British Islands; but it is to a peculiar structure of this portion of the eye in these fishes that I wish to direct particular attention. On attentive examination of this portion of the iris of these fishes, it is seen that on the anterior portion the surface is smooth, and not, as in birds, striated and irregular; but in its substance the texture is loose, and viewed under a microscope it appears to be composed of an exceedingly fine, but irregular network, which is not composed solely of vessels, but is more loose about the middle distance between the pupil, or inner border of the iris, and its outer circumference; and it becomes more condensed as it approaches the pupil in one direction and the circumference on the other. At what may be termed the border of the pupil there is a condensed rim of the same texture, so that the iris itself has a finely granular appearance, and the condensation is directed along even the border of the fringes of the dependent curtain; which portion of the iris, if we may judge from the difference of appearance it

presents at different times, possesses a power of dilation, or extension and contraction. In some examples of the fishes on which these observations were made, the curtain was only let down sufficiently to hide half the space of the pupil, while in others little of it could be seen until it was brought down into sight by the aid of the point of a needle, and again in others it extended so far as to shut up the whole of the pupil, except what could be discerned between the intervals of the fringe.

And not only do these curtains present a different appearance in different individuals, but even in the same fish this extension of the curtain shall be widely different in each eye, so that in one it shall almost entirely cover the sight, and in the other it may be scarcely capable of being discovered; a circumstance which goes far to show that the eyes of at least many fishes have a power of vision independent of each other, in a manner or to an extent wholly unlike what we perceive in ourselves, or in any animal of the land. The muscle discovered by Mr. Dalrymple, which influences the position of the crystalline lens of the eye, is present in that organ in the Pleuronectidæ, and also in the rays; but the curtain we have described appears to be the more required in the last-named fishes, from the circumstance that their range of action is often from a considerable depth of water, at the bottom to the broad daylight of the surface.

In the toper, the pupil is simple, without those appendages which we observe in the rays, and in its form transversely ovoid, furrowed on the surface, and in some examples much larger than in others. A remarkable circumstance connected with the eye of this fish is, that if, when newly taken from its native element, it be laid on its side in such a manner as to keep one of its eyes altogether out of the influence of light, the pupil of the darkened eye will become dilated, while, if the light be strong, the other will become contracted into an irregular line, and folds will be discerned in it, radiating more especially to the inferior border, and yet, on its anterior surface, there could not be seen any appearance of fibres, nor any special organization beyond the folds produced by the contraction, which were of a radiating and not a circular character, and those were for the most part near the margin of the pupil. Something similar to this occurs also in the picked dog, but there is so far a difference that the pupil in this specics is perpendicularly ovoid instead of being transverse, and there is no regularity of action in its contraction and dilation as regards the comparison of one with the other, but each of them claims an entire independency, so that uniformity between them is altogether a matter of accident.

But however difficult it might be found to discover the muscular fibres of the eyes of these fishes while they were

even and regular, though wider on the outer side of the major axis than the inner; in the other they are altogether irregular, with three or four obtuse angles, and a large distinct nucleus.

The subgenera of Hyporhodii are the following-Volvaria, Pluteus, Entoloma, Clitopilus, Leptonia, Nolanea, Eccilia. The two first of these have the gills absolutely free; in the remaining divisions they are variously attached, though sometimes very slightly, and often separating from the stem at maturity.

The first subgenus, Volvaria, which derives its name from the volva being developed as strongly as in the most noble Amanita, and whose species in many respects approach Agaricus cæsareus, figured in the number of the INTELLECTUAL OBSERVER for April, 1865, No. 39, contains a few very fine species. The hymenophorum is perfectly distinct from the stem, and though the universal volva is so highly developed, there is no partial ring, a peculiarity which is observable in the whole of the series. The gills are regularly rounded behind, and sometimes they almost adhere together like the gills of Coprini, in consequence of the high development of the cysts which are scattered over them. They are moreover inclined to be deliquescent, and agree with the fugitive Coprini in their affecting richly-manured spots, very decayed wood, or fermenting vegetable matter, as tan. They are not in general reckoned esculents, though Agarius parvulus, which abounds in rich grassy pastures, often gets into the mushroom basket, either wilfully or accidentally. Viviani seems to think that all the species of this subgenus are esculent, but he very wisely adds a caution that we must wait for experience till we make any positive assertion in the matter.

Agaricus volvaceus sometimes grows in great abundance on spent tan in hothouses, and one or two closely allied species, but with a viscid pileus, occur now and then on the sides of pathways, Agaricus coffee, Viviani, has been found only on coffee-grounds left to ferment for some months in a stove in the botanic garden at Genoa. Another mushroom, A. Neapolitanus, which is of a beautiful snowy white, and not like the last reddish and streaked with darker lines, and apparently of very different affinity, as the gills are very decurrent and there is no mention of a volva, is procured in some quantity at Naples in a similar way, and is constantly eaten. The coffeegrounds are put into an earthern unvarnished vessel, which is placed in the shade and slightly watered occasionally, and the fungi appear at the end of six months. I tried more than thirty years ago to obtain it in the same way in England, but was not successful, perhaps from not having a sufficient quantity of coffee marc at my disposal.