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Show 1901.] ANNELID OBTAINED UURING THE "SKEAT EXPEDITION." 81 138. NETTOPUS COROMANDELIANUS (Gm.). Anas coromandelianus, Gm. S. N. i. 2, p. 556 (1788). Nettopus coromandelianus (Gm.), Oates, op. cit. ii. p. 272; Salvad. Cat. Bds. Brit. Mus. xxvii. p. 68 (1895). a, b. 8 2 . Patelung. 30th March, 1899. 139. DENDROCYCNA JAVANICA (Horsf.). Anas javanica, Horsf. Tr. Linn. Soc. xiii. p. 199 (Java) (1821). Dendrocycna javanica (Horsf.), Salvad. Cat. Bds. Brit. Mus. xxvii. p. 156 (1895). a. 2 - Tale Nowy, Patelung. 2nd April, 1899. b. 2 • Tremangam. 12th July, 1899. 7. On a Freshwater Annelid of the Genus Bothrioneuron obtained during the " Skeat Expedition " to the Malay Peninsula. By F R A N K E. B E D D A R D , M.A., F.R.S. [Eeceived January 14, 1901.] (Text-figures 8-10.) There are at present only two species of this peculiar genus Tubificidre known : they come from such widely separated localities as the neighbourhood of Praguel and the neighbourhood of Buenos Ayres2. 1 believe that the facts ascertained from an examination of specimens from the Malay Peninsula justify me in the creation of a third species. The worms are of about the same size as average specimens of Tubifex rivulorum, and thus present no divergence from the.two other species of Bothrioneuron. The prostomium is conspicuous and of the ordinary form that it exhibits among the Tubificidae, as will be seen from an inspection of the two drawings (text-fig. 8, A, B, p. 82). Prostomial sense-organs.-I find in the present species the same prostomial sense-organ which I described and figured (in section) in Bothrioneuron americanum. It is, moreover, also unpaired in the present species. The position of the organ, however, varies : it is usually on one side, which is preferably the left, just at the junction of the convex upper surface of the prostomium with the lower surface. In one specimen, however, it is exactly in the middle of the lower surface, and in another it is as distinctly upon the upper surface, and also fairly median in position. The organ is very decidedly upon the prostomium itself; it is not situated at the junction of the prostomium with the peristomial segment, as is the case with the corresponding organ of B. americanum. The one specimen in which the sense-organ happened to be ventral in position is shown in the accompanying drawing, by 1 Stole, " Mon. Ceskych. Tubificid.," Abh. Ges. Bohm. (2) vii. p. 43. 2 Beddard, Hamburg. Magalh. Sammelreise, Naidert &c. p. 6. PROC ZOOL. Soc-1901, VOL. I. No. VI. 6 |