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Show 1885.] NEW-ZEALAND EARTHWORMS. 823 mentioned, the setse are in four series of pairs, the nephridia similarly alternate in position from segment to segment (woodcut, fig. 2). There does not, however, appear to be any regularity in this alternation: sometimes the nephridia of five or six consecutive segments open by the same series of setse on both sides of the body. In other segments there is an asymmetry of the nephridia of the twro sides of the body : for example, the left-hand gland may open by the dorsal, while the right-hand gland opens by the ventral pair of setse ; occasionally Acanthodrilus novce zelandice.-A portion of the body viewed from the side. n, nephridial pores; s, setse of ventral pair. there is a regular alternation coupled with absolute symmetry in the position of the nephridial pores. Moreover, no two individuals of either species that I examined were exactly alike in these respects ; and it was impossible to distinguish one species from the other by the position of the nephridial pores ; occasionally the nephridia, one or both, were found to coincide at the same series of setse as the male and female genital ducts, but in no case did I observe a similar coincidence of nephridium and spermatheca. Another point of interest in connection with the nephridia of these two species has not been recorded by Perrier in Plutellus: the two series of nephridia, dorsal and ventral, show other indications besides the varying position of their apertures of being the vestiges of two complete series; in every instance it was found possible to distinguish the nephridia of each series by morphological differences. In all the nephridia the muscular portion which forms the distal extremity of |