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Show 1903.] OLIGOCHiETA FROM NEW ZEALAND. 209 with the supra-intestinal vessel. As I have studied the specimen only as an entire object, I cannot say anything as to the structure of this organ, but it seems to resemble in its external features the " blood-gland " which Beddard describes as occurring in segments xii., xiii. in P. subterraneus. Dimensions. 15 m m . xf m m . It is much stouter than P. lacustris, and consists of 70 segments. Locality. Lake Taupo, North Island, N e w Zealand. TAUPODRILUS, gen. nov. TAUPODRILUS SIMPLEX, sp. n. (Plate X X I V . figs. 1-9.) Of this worm I found about a dozen individuals, most of which are only the anterior ends, and a few are entire. They are all much coiled, rendering it a matter of some difficulty to make sagittal sections. The following account is based on the study of three individuals, more or less sexually mature, stained and mounted in Canada balsam, and a series of longitudinal sections through the anterior segments, and transverse sections of the middle region, in addition, of course, to the usual glycerine and potash preparations. The prostomium is conical and relatively long. Chcetce.-The dorsal bundles consist of capilliform (at any rate in the anterior segments), accompanied by bifurcate chaetae (PI. X X I V . fig. 3), with a few delicate intermediate teeth. Such chaetae may be termed " multidentate" or " ctenate," and occur also in Tubifex rivulorum. The ventral bundle consists almost wholly of crochet-shaped chsetae, with intermediate teeth. In the dorsal bundle there are one or two capilliform and usually three or four ctenate chretas (in one individual the former were only present on segments v., vi., vii.; in another they did not begin till the fourth segment, and in one specimen I was unable to detect them), and typically they occur only on the first 12 to 15 chsetigerous segments. In the "ctenate" set the chief teeth or prongs are scarcely curved (PI. X X I V . figs. 4, 4 a), and the number of intermediate teeth varies from two or three to several; usually they all separate, but in a few instances a delicate striated membrane unites the chief teeth as in " Psammoryctes." The dorsal chsetse of segment ii. are smaller than the rest. In the ventral bundle there are from 4 to 6 chaeta? in the anterior segments, diminishing to 3 or 4 in the mid-body. The chief teeth are curved as in normal forked bristles or crochets ; the upper tooth is less stout than the lower, and over the greater part of the body the two teeth are of the same length, but in the anterior segments the upper tooth is slightly the longer (PI. X X I V . fio-s. 5, 6). Generally, all the crochets in a bundle have intermediate teeth, which lie in a different plane from the main teeth ; but in the anterior segments a minority in each bundle are normal crochets. PROC. ZOOL. Soc-1903, VOL. II. No. XIV. 14 |