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 pieces of strong class a couple of inches square. t» each of which is cemented with gold size or marine glue an indiarubber ring about one-eighth of an inch thick. These, when piled on one another, and held together by indiarubber rings, take up but little space. Lastly, for these coarser plants nothing answers much better than to screw them up in bits of strong paper and bring them home in a wide-mouthed bottle, tin box, or even loose in the pocket. A specimen need, at any rate, never be left behind for want of a more elaborate vasculum.

The Desmidinceæ require more care, and the gathering should be transferred with as little shaking as possible to one of the glass tubes which should he filled with water.

It is a useful plan, when out for a long walk, to number the specimens. and note down their exact habitat in a pocket book. Some years ago the writer returned from a five and twenty mile walk across the Welsh Mountains, with some fifty "dips" of all sorts, Next day was devoted to their examination, and in one tube, among a quantity of common species, were found two frustules of Dogidium rodgsum, a Desmid hitherto recognised as exclusively an American species, but which has been since found, we believe, by Mr. Archer, in Ireland. Unfortunately. no such record as we suggest had been kept; and, although the writer stated off next morning at daybreak, took exactly his previous route, and searched sedulously till nightfall in every tiny pool in which he remembered dipping in his previous ramble, not a trace of the new plant was found.

The specimens being brought home, each should be transferred in turn to a small saucer, or water-glass, and portions of it examined under a convenient power, generally about half an inch. If any new species is spotted, it should be set aside for mounting, duly labelled temporarily; but, if the gathering seem to contain nothing but old friends, it is a useful plan to give it a parting squeeze between the fingers, and catch the dippings in a watch-glass, Small Desmids and Diatoms, previously entangled, are pressed out in this way, and new species often reward the examination. The squeezed mass should not be thrown away till the washings have been searched over. It often pays to repeat the process.

A specimen should never be thrown away because it is a poor one, or consists of one individual. where a dozen would be acceptable. The rarest plants are naturally often met with singly, Once, in examining a mass of very dirty stuff from a Welsh bog, the writer pounced in his first dip on the rare Desmid, Micrasterias radiosa. Rashly concluding that there were sure to he plenty more, he swilled back the contents of the slide into the mess. But dip after dip, and washing after washing, were examined in vain; end, as the species was too rare to be lightly lost, it cost the work of two long nights to haunt over the entire mass, drop by drop, till the individual plant, whose diameter was about 1-140th of an inch, was recovered.

We say, therefore, ''mount a poor specimen rather than none. If you find a better you can throw it away or give it to a friend, who will value it''.