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Show 380 MR. F. E. BEDDARD ON TWO [Apr. 17, Western than in Eastern Africa. I have already described several species of a genus nearly confined to Western Africa, viz. Gordio-drilus; and at Lagos a species of Pygmceodrilus also exists. The same two genera also occur on the West Coast, but the former is there not nearly so common. The present paper increases the number of West-African Cryptodrilids by three ; and I refer these worms to two new genera. Nannodrilus africanus seems, from the large number of specimens sent to me, to be an exceedingly common species. It is a curious fact that both of the two genera show certain resemblances to the Eudrilidie : there is, in m y opinion, little doubt but that the Eudrilidae are derivatives of the Cryptodrilidae; but I cannot agree with those who would unite two such extremely diverse types in one family. I shall now direct attention to the anatomical characters of the new species, beginning with a definition of the first genus, which I propose to call after Mr. Alvan Millson. Millsonia, gen. nov. D E E . Large worms with strictly paired setce. Male pores (single or paired) upon xvii. Two gizzards in v., vi. ; calciferous glands, three pairs in xv.-xvii. ; intestine with about 30 pairs of cceca, a pair to each segment. Nephridia diffuse. One pair of spermathecce without diverticula ; spermiducal glands tubular ; no penial setce.-Hab. West Africa. This definition will differentiate the present genus from any other Cryptodrilid at present known. The two most salient characters of the genus which are peculiar to itself concern the nephridia and the intestinal caeca. These alone would serve to distinguish the genus ; it is principally on account of them that I unite the two species, which I shall describe, into a single genus. These two species, as will be seen in the course of the following pages, differ from each other in a good many points of, as I believe, subsidiary importance. The two matters referred to are not exactly novelties of structure in the group, but they are exaggerations, so to speak, of characters already found in allied forms. The caeca are precisely like those of the genus Perichceta only that there are so many of them. In Perichceta sieboldi and in one or two other species there are, it is true, six or seven pairs of these appendages of the intestine; but then they are all contained in one segment; whereas in the genus Millsonia they are contained in as many segments as there are pairs of caeca. The existence of these caeca is interesting as tending to knit still closer together the, in other ways not very remote, Cryptodrilidae and Perichaetidae. The second peculiarity of this genus concerns the nephridia. The structure of these organs will be described more at length immediately; but in the meantime attention may be directed to the fact that they present the curious appearance illustrated in the accompanying drawing (fig. 1, p. 381). The excretory tubes of the posterior segments of the body have ceased altogether to look |