The Rev. A. E. Eaton, on his return from the Expedition of the Transit observers to Kerguelen’s Land, placed in my hands for description two small earthworms obtained by him in the island, and preserved in strong spirit. The specimens were small and immature, not exceeding 1½ inch in length; hut by cutting transverse sections of one, and slitting the other up the median dorsal line, staining with carmine, and mounting in Canada balsam, I have succeeded in making out the affinities of the species. The study of the various species of Earthworms (Lumbricidæ proper) has only recently been attempted with due attention to anatomical detail. Their excessively complicated generative glands, ducts, and pouches present the greatest diversity of arrangement, so as to enable us to establish a series of strongly marked genera, which, while differing in the arrangement of these parts, yet present but slight differences in external form, or in the arrangement of their setæ. Professor Edmond Perrier, availing himself of the very fine collection of exotic Lumbricidæ in the Jardin des Plantes, has been the pioneer in this branch of investigation, and in his memoir "Recherches pour servir a l’histoire des Lombriciens terrestres," published in the "Nouvelles Archives du Muséum d’Histoire Naturelle, 1872," he has established a series of genera on the only possible characters in modern zoology— namely those derived from thorough anatomical examination. M. Perrier has studied earthworms from North and South Africa, from the East Indies, from the West Indies, from North and South America, and a number of scattered islands, and has rendered it evident that he has tapped a rich storehouse of zoological facts of first-rate importance. Presenting, as they do, a considerable number of genera, and occurring as they do almost universally on the earth’s surface where there is vegetable soil—being moreover absolutely destitute either of means of transport or of power to resist deleterious agents whilst being passively transported (earthworms and probably their eggs are rapidly killed by sea-water), the Lumbricidœ promise to yield, when fully investigated, a mass of information bearing upon the problems of the causes of geographical distribution and the connections of continents and islands in past epochs—more decisive and indisputable in its character than that presented by any similar small group of the animal kingdom. The essential feature of their organisation which gives to the Lumbricidœ so interesting and important a position, is the possession of a most sensitive generative apparatus— sensitive , that is to say, in the sense of responding by innumerable modifications of its highly-developed male ducts, prostatic glands, seminal reservoirs, penial setæ, copulatory pouches, and other accessory glands, to those slight differences of environment which whilst thus affecting the genitalia so as to create generic distinctions, have yet left the external form and character unaffected.
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