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Show 612 MR. F. E. BEDDARD ON THE [May 22, chcetus and in a few other species. Here, again, there are not data to enable the character to be made very wide use of. In the following pages I have made use of some or all of the characters formulated in the two lists just given. I have also directed attention to size, because it is inconvenient to describe a species without giving some notion of its dimensions. As a matter of fact, size seems to be of practically no importance in the discrimination of species. Neither has colour any practical importance. For, in the first place, the colours of earthworms do not as a rule show easily describable variations from species to species; in the second place, there is no doubt that actual variations do occur from individual to individual; and, finally, the bulk of the existing species are known from spirit-preserved specimens, from which in many cases all, and in others some, of the colour-markings have been lost. Nor does it seem to be very profitable to dwell strongly upon the number of setae in each segment; at any rate the value of this character has been distinctly exaggerated. The form and extent of the buccal lobe shows only such slight differences from species to species, if any at all, that I have ignored it. In the following survey of the species I have arranged them in a number of groups for purposes of easier reference. It should be noted that in all the descriptions-unless any remark be m a d e - the following characters are to be added :-Clitellum occupying segments xiv.-xvi. Male pores on xviii. Oviducal pore on xiv. Dorsal pores commencing about xi./xii. Gizzard in viii. Caeca present in xxvi. Last heart in xiii. Testes in x., xi. Ovaries in xiii. Sperm-sacs in xi., xii. Genus AMYNTAS, Kinberg. Syn. Ehodope,Nitocris, Pheretima,Kinberg. Perichceta, Schmarda. Megascolex, Baird. Large (4 feet) to small (1 inch) earthworms. Segments of body comparatively few, often corresponding with length in millimetres. Prostomium never continued by grooves to end of the first segment of the body. Setae (sometimes ornamented with faint ridges) forming a continuous circle, occasionally interrupted in the ventral and dorsal mid-line, or in either the dorsal or ventral mid-line. Setae vary in number from about 20 to over 100 on a segment; sometimes stronger on the anterior segments, and at times two or three longer on each side of ventral median line. The setae are sometimes more crowded ventrally or laterally than dorsally. Clitellum as a rule occupying segments xiv.-xvi., often beginning in the middle of the first and ending at the middle of the last of these segments ; rarely extending beyond the xvith. Clitellum developed all round the body, with or without setae. Only in A. houlleti are the clitellar setae different from those on other segments. Dorsal pores as a rule not commencing before segments xi./xii., always present. Male pores on xviii. Oviduca |