Page:The Zoologist, 1st series, vol 1 (1843).djvu/221

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Daphnia brachiata.

minute crustaceous insects which were arranged by Muller under the general name of Entomostraca, meaning insects inclosed within a shell, have met with very little attention from the naturalists of Great Britain. Their exceeding minuteness and extreme delicacy of structure, have perhaps been the causes of this neglect, deterring most naturalists from examining them and studying them as they require to be studied—fresh from their native habitats. The difficulty of preserving them obliges the naturalist to seek them in their secret lurking-places—the fresh-water ponds and ditches, and the little pools in the rocks on the sea-shore, where they are chiefly to be found, and to study them as it were on the spot, with the aid of his microscope. The celebrated Latreille, after some remarks upon this extremely interesting class of little creatures, observes, "The organs of mastication are almost to this day hid from the eyes of observers. How can we discover a part which does not constitute the tenth part of a microscopic animal? The eyes of De Geer and Jurine however have believed that they could distinguish something. The latter has remarked, in the Monocle puce of Linnaeus, two mandibles without teeth &c. These observations are so delicate, that out of a hundred entomologists, scarcely shall we find two or three who are able to repeat them, and participate, in some sort, in the pleasures of that discovery." Since Latreille penned the above, our knowledge of the anatomical structure of these marvellously small creatures has been much extended, and the few naturalists who have had patience to repeat the observations alluded to in the above quotation, have, I am sure, fully participated in the pleasures enjoyed by the first disco ver