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edges of the sand-ripples on the sea-beach, where the furrows left by the retired tide stand filled with water. The edges of those furrows often present a more or less dark ocherous brown appearance, and that peculiar colour is caused by myriads of diatoms, which, under ordinary circumstances, lie buried in the sand, having risen to the surface attracted by the sun's light and heat. To prevent disappointment, it may be said that in searching for diatoms on the beach, it is possible that for several days, or it may be weeks, few or no indications of their presence may appear; but if the search be continued with perseverance, success will certainly reward the investigation. It is difficult to account for the changes which take place in the times and circumstances in which diatoms appear on the sea-coast. I have seen them in great abundance in July and August of one year, and in the next year, although the weather was bright and appeared favourable, they have not made their appearance in large numbers until September or October, and then the beach was covered with matter of a deep coffee-brown colour, which, on being gathered and examined, was found to consist entirely of diatomaceous frustules.

The apparatus requisite for hunting diatoms on the sea-coast are, half-a-dozen two oz. bottles, one four oz. bottle, with wide mouth, and an ordinary dessert spoon. The best method of gathering is to take the spoon, and with it shave off the ocherous brown matter that lies on the surface and colours the sand, put it, with the sand and water that are taken up at the same time, into the wide-mouth bottle. When the bottle has been half filled with colouring matter, sand &c., let it be well shaken; the sand immediately subsides, and the water is left tinged with a more or less deep cloudy-like brown, all of which colouring matter consists of diatomaceæ. When the bottle has been shaken, and the sand allowed to subside, which it does almost instantly, then the supernatant fluid should be poured into a clean bottle, the contents of which would then constitute the gathering; the sand may be thrown away, and the large bottle cleaned in readiness for another collection. The following new forms, together with about one hundred others, registered in "Smith's Synopsis," and "Pritchard's Diatomaceæ," are to be had in large numbers near the high, middle, and low tide marks. Near high tide mark Attheya decora, Cocconeis excentrica, Navicula clepsydra, N. trevelyana, Donkinia carinatum, &c.; and at the middle and low tide zones, the following forms abound:—Pleurosigma lanceolatum, P. arcuatum, Donkinia rectum, D. carinatum, D. minutum, Druridgia geminata, Toxonidea Gregoriana, T. insignis, Bacillaria cursoria, &c., nearly all of which are very beautiful, and the majority of them so delicately marked as to afford the best possible means of testing the excellence of first-class objectives. Newcastle-on-Tyne.T. P. Barkas.

Notwithstanding the recent and very interesting volume on this subject, it is not yet exhausted. Fresh facts may be gathered about what has already been done, and result in the contemplation of animal life in the highest phases of its intellectual or instinctive development. The infinite variety of means by which one end is to be attained is marvellous. To multiply its kind, and provide a home and shelter for its future offspring. is the great idea which pervades all forms of life, This is more or less elaborated in different individuals, but in all the same object is paramount. Two or three instances may be given here, which possess in themselves another interest, of an economic character.

Trehala.—A singular substance has long been known in the East under the name of Trehala or Tricula. It consists of oval cases from half to three-quarters of an inch in length, found attached by one side to twigs of a species of Syrian Echinops. The external surface is rough and irregular, nearly of the colour of Sicilian manna, hard, brittle, and with a sweetish taste. These cases are constructed

by a little beetle (Larinus subrugosus, Chevr.), of which a figure is given (fig. 1). "It appears that the larva of the Larinus collects a considerable quantity of saccharine and amylaceous matter, which it procures from the Echinops, and that it constructs its dwelling by disgorging this matter and moulding it with its rostrum." Each case contains only one individual, and when this has assumed its perfect form it emerges from the orifice at the upper end. There is much in the history and economy of this little insect which is still a mystery to us, but enough is known to make us wish for more. Analysis of these curious nests has shown that they contain gum, starch, and sugar in their composition, and when thrown into water, at the ordinary temperature, they swell, partly dissolve and become converted into a pasty mass. In Turkey and Syria they are collected and employed as food, many being sent to Constantinople and other Turkish cities, where they are regularly offered for sale. Some of this substance was exhibited in the Turkish department of the Great Exhibition of 1851. The insect itself is of an oblong form and black, about three-fifths of an inch in length. Its snout is projecting, with the antennæ attached on