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Show 1892.] SPECIES OF EARTHWORMS. 699 of their affinity ; Gordiodrilus is clearly a rather degenerate form, with no marked affinities to any other genera except to Ocnerodrilus and Pygmceodrilus-an affinity which may be merely due to the fact that they are all degenerate forms, and thus not a real affinity. In any case it is remarkable that this curious form of glandular tissue should be limited to the calciferous glands of the two genera Eudriloides and Gordiodrilus. As regards the rest of the alimentary canal, there are not many points which require notice; there is a gizzard in the fifth segment, well developed and by no means rudimentary. The first septum lies just in front of the gizzard and thus separates segments iv./v. ; the four septa which follow the gizzard are thicker than the rest. The nephridia are of course paired, and the first pair appear to belong to the fourth segment. There is only a single pair of testes, which lie in the xith segment, attached to the front wall of that segment; opposite to them are the funnels of the sperm-ducts, these are very large and much folded. The sperm-duct has no swelling at its origin from the funnel; it is a narrow tube, much narrower than the oviduct; it opens into the atrium a little way before the opening of the latter into the terminal copulatory apparatus. The atria are two closely applied tubes contained within one sheath, so that on a dissection the atrium would no doubt appear to be single. Whether the division of the atrium is an indication of its being the result of the fusion of two separate atria is not obvious ; at first sight it does appear to be obvious, but it will be remembered that in Eudrilus each atrium is similarly divided into two completely separated tubes within a common sheath. This atrium consists entirely of a layer of glandular cells ensheathed in a very thin peritoneal layer ; the terminal apparatus is a muscular diverticulum of the body-wall, with which are also connected a pair of sacs each containing a single penial seta, whose shape I am unable to describe. The spermatotheca is unpaired, it opens on to the exterior in segment xiii. ; the aperture leads into a thick-walled sac from which arises a thinner-walled sac extending backwards into the next segment; this latter is lined by cells which appear to be similar to those fouud in the corresponding organ of other Eudrilidae, and suggest that in this species as in others the spermatothecae are developed from the ccelom, and are therefore not homologous with the spermatothecae of other Earthworms. The terminal sac of the spermatotheca is lined by an epithelium which has preserved the characters of the epidermis whence it is derived; the cells are of two kinds, the usual glandular and the interstitial cells. To the spermatotheca on each side is attached a receptaculum ovorum ; these sacs, although attached to the spermatotheca, are not really connected with it, that is to say they do not open on to the spermatotheca; the egg-sacs are not in any way unusual in their structure, their cavity is divided up into numerous compartments by trabeculae. In the compartments are lodged the ova: the ova in the egg-sacs are not accompanied by masses of developing ova or by |