recorded, prove that it is not accidental, but due to some cause operating generally in their formation.

I bring these remarks forward, in the hope that further observations may be elicited from some of our members or others, on the phenomena of the storm, as well as to draw attention to the importance and interest of this branch of meteorology, in case future storms may afford opportunities of detailed observation.

Observations on keeping Salt-water Fish alive for a considerable time.— By LT.-COL. R. C. TYTLER.

[Received 28th Feb., 1864.]

[Read 6th April, 1864.]

In offering the following observations for publication, I should here remark that they are entirely the result of a great many experiments, made during several months of my stay at Port Blair, and which I am happy to say have been completely successful.

1. If fresh water from the sea be put into a vessel and changed every twelve hours, sea fish will live in it.

2. It requires a quart beer bottle full of sea water, to keep a fish the size of a minnow alive for twelve hours.

3. After twelve hours, the water begins to be offensive, (from the escape of Sulphurretted Hydrogen ;) the fish comes to the surface, swims in circles impatiently, and dies before twenty-four hours: the water about this time becomes most offensive.

4. If salt water be put into an iron vessel and boiled over a brisk fire till nothing but the dry salts remain, it will be found that a tea spoonful and a half of this salt, added to a quart beer bottle of fresh tank water, will keep alive a fish the size of a small minnow, for a considerable length of time, without any change of water being required for months this simple fact took me months and months to arrive at, and it now affords me the greatest pleasure to make the result of my successful experiments known.

5. No food should be given to the fish, beyond a fly or smashed cockroach now and then.

6. Freshly caught fish should be kept in a vessel at least twenty-four hours by themselves, before being placed with those already in the aquarium.

7. To prove how successful the above plan has been, I should here add that I have brought fish alive from Port Blair to Calcutta that had at least been three months in the same water, and the latter was as fresh as possible up to that time.

Observations on a few Species of Geckos alive in the possession of the author.-By LT.-COL. R. C. TYTLER.

[Recieved 27th March, 1864.]

Port Blair, 1st January, 1864.

On several occasions lately, interesting living specimens of Geckoid Lizards have been brought from the jungles, which has induced me to make an attempt to keep them alive, for the purpose of observing their habits more closely, than appears generally to have been done; in order to accomplish this object I have been obliged to resort to many expedients, and the only one that has proved successful has been the following: I have had a great many boxes made of light deal wood, two sides of which are glass: the wooden portion is perforated with holes in every direction, so as to admit of air passing freely through: one of the glass sides forms a slide to allow of the box being opened when an animal is put into it; at one end of the box is a small tin trough for water, similar to that used in Canary cages and at the bottom there is an inch of clean sand: a small branch put into the box for the use of Arboreal species, completes the arrangement, the tin for water is always kept full, and a number of living flies, or young cockroaches are kept loose in the box, and I find that this is sufficient for all the requirements of these Lizards.

My boxes vary in size, but the most convenient are 10 inches by 6, and two inches wide, or 6 inches by 4, also two inches in width; but as the glasses are liable to accidental breakage, I have in a measure contrived to provide for and meet this, by having a separate light wooden box made, capable of holding six of the glass cases: this not only protects the glass, but keeps the freshly caught animal quiet, from being in the dark, and undisturbed, which it greatly prefers; and prevents the restlessness it shews on such occasions in the light.

Without in any way wishing to question the existing classification of saurian animals adopted by naturalists, I feel in the present

instance, while studying the forms, and closely examining the habits of the geckos now alive in my collection, that it is incumbent on me simply to adopt the genus Gecko, for every species in the family, rather than place them in the several genera, enumerated in modern classification. Geckoid lizards bear a strong similarity to each other, and are in themselves unmistakable. One specimen alone is almost sufficient to mark the entire type, notwithstanding that on comparing species, one with another, a marked difference is visible, quite sufficient to distinguish species, but insufficient in my opinion for a division of the genus Gecko into genera, to meet alterations caused by size, or slight differences of form. I have therefore adopted the genus Gecko for all these lizards in my collection, whose habits I have lately been enabled to observe closely. The word Gecko, is evidently taken from the sound, uttered by very many of the species, in which 'yecko,' or gecko,' or 'chucko,' is distinctly audible. From the formation of the pupils of their eyes, it will at once be remarked, that they are more or less nocturnal in their habits. In many the pupil strongly resembles that of a cat, when much contracted. In the day, it is contracted to a fine dark hair line, but this is only the case with those which are most nocturnal; others again which are diurnal in their habits, preserve the fullness and rotundity of the pupil in ordinary strong lights: this is the case with my Gecko chameleon (Phelsuma Andamanense of Blyth,) a very beautiful species, peculiar to the Andamans, where it is found in great abundance. The pupil of this species remains round in all lights, and is intensely black; whereas, in my Gecko pardus, which, I think, may prove to be Hemidactylus coctai auctorum, the irides, which are of a peculiar bronze and very metallic hue, shew during the day simply a very fine vertical hair-like pupil. Almost all the other small species have the same, but in Gecko toucktay of mine, which is Platydactylus verus, the irides, which are of a yellowish green, instead of having by day-light a hairlike contracted pupil, have five or six minute unconnected dots vertically arranged, which, on the reduction of light, rapidly increase and connect themselves, forming in the dark a full pupil. This latter I ascertained from a gecko that had died in the dark, the pupil of which I found to be fully developed and round. Geckos seem to feed entirely on insects; the localities which they frequent therefore, are those best suited to the description of insects they feed on, for capturing which, nature

has given them remarkable peculiarities, admirably adapting them for capturing their prey. I allude to the extraordinary power they possess of changing their colours, so as to adapt themselves to the various localities which they frequent, and by which their complete concealment is effected. In Gecko Chameleon for instance, when in dark places, or in the earlier part of the day, the colour is almost black with red markings, and this remains under ordinary circumstances till nearly midday, when a gradual change takes place, and the dark hue gives way to an intense emerald green on the body, with a bright blue on the tail, the under surface becoming of a fine canary yellow, and the red marks still remaining on the back. By one or two o'clock, the change of colour is complete, and the animal sallies forth from his dark place of concealment, on to the bright green leaves of trees, in quest of insects: but the change of colour may take place at any time during the day, according to circumstances of position and light; for if one of the green coloured lizards be placed in a dark spot, the colour changes to a dark hue, in the same ratio that the dark animal becomes green when placed in the sun, or in a strong light on the leaves of trees. The change of colour is also influenced by the seasons, for during the rains the change is not so rapid as it is in brighter weather.

The casting of the skin is of frequent occurrence with all the Geckos, but particularly so with Gecko Chameleon, and, strange to say, other lizards in the same case, devour the skin as soon as it is cast in many instances I have even seen them tear it off before it was fairly changed. All Geckos are great water-drinkers; they drink by lapping with their tongues like dogs; it is therefore very necessary to keep the little tin trough in their cage constantly supplied with water. Insects should also be kept in their boxes to satisfy their voracious appetites. Though insect-eaters, and at times greedy and voracious, still they are capable of enduring hunger for a considerable length of time, without seeming to suffer any inconvenience from it. One of the most marvellous traits in the habit of the Gecko, is its power of frequently and most rapidly changing its colour, and also its markings, to suit the places it may be in; I have seen an animal become, from a light straw-colour, speckled all over with dark marks; and perhaps in another instant of time almost black or a light slate. No chameleon can change more rapidly or perfectly than the gecko. In Gecko chameleon, the change is more apparent and striking, owing simply to the contrast between an almost

black color and a brilliant light emerald green, but this change is not more remarkable than that which takes place in the more humbly coloured species; for in many, not only the general colour changes, but brilliant markings suddenly appear, which were previously invisible. An animal which is of a dull grey and transparent, and without any apparent markings, when examined in one of my boxes and held up to a strong light, may, when placed in a more subdued light, assume a brilliant tortoise shell hue, or a light straw, or perhaps become nearly black such extremes and differences in colour are truly surprising.

:

Most Geckos have five distinct toes. The thumb is more or less defined, and the toes are furnished with or are without sucking pads, possessing more or less adhesive powers; those which have the pads less developed, or confined to the tips of their toes, find greater difficulty in ascending plane vertical surfaces than those which have the suckers fully developed. In some of the small species which frequent walls, a membrane unites the toes, while others possess membranes on the sides of their tails, heads and bodies; according to which characters the group is separated into several genera. A peculiarity in the claw of the gecko is its powerful retractility, which in some species is not confined to the claw, but is in a great measure possessed by the entire toe: the sucking pad is even capable of reduction, either by a folding process or an internal retraction. Another strange peculiarity is in the eye, which is furnished with a transparent case, behind which, the eye moves freely and rapidly.

In casting their skins, the portion over the face draws off from the nose towards the occiput, leaving the case of the eye, in some, unchanged. This, it will be perceived, is different from the process which obtains in the case of a snake when casting its skin, for in the latter case, the case over the eye is invariably renewed with the skin. I have already alluded to Geckos being entirely insect-eaters, and they are active insectdestroyers; but for all that, they are remarkably choice in the selection. of their prey, as they may be seen for a considerable length of time, perfectly motionless on a wall, watching some particular insect they may have selected for their food; and they will, in the meantime, allow numbers of others to pass their very mouths, without making the slightest effort to secure them. Flies and cockroaches form a very favourite food, but the insect must be alive, or they will not touch it.