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Show 3 8 MU. W. F. LANC1IESTEK ON THE SIPUNCUL1DS [Jan. 1 7 , Examination under the microscope of the skin of the introvert shows that, for about half its length, the papillae are similar to those on the body, but that anterioi'ly they gradually become flatter, the plates becoming much smaller and losing their concentric arrangement, so that the whole appears as a granular area surrounding the central opening. In the dorsal half of this anterior region, moreover, they become surrounded by thick bands of brown pigment which form a dense network between them and tend to obscure their height, but in the ventral half the pigment is absent and it is easy to trace their gradual flattening (PI. II. fig. 1 c). This species is obviously very like Ph. psaron, but there are certainly no spines on the introvert and the papillae differ in certain features. Thus Sluiter says " Sonst kommen im Riissel nur dunkle Leisten vor, aber keine gesonderte Papillen," which hardly agrees with the arrangement found here. Otherwise the general anatomy is closely similar, save only that the nephridia are half and not three-quarters the length of the body, and attached for two-thirds and not one-third of their own length. Sluiter's description is rather brief and he has not figured his species, but I feel reasonably certain that the two forms are distinct. 7. P hyscosoma g a u d e n s , sp. nov. (P la te II. fig. 2 .) Loc. Pulau Bidan, Penang. Thi •ee specimens. This form would appear to be the Eastern representative of the Western Ph. weldonii Shipley. In all general features .it closely resembles the latter, but in regard to the papillae of the body it is distinctly different; these consist, in Shipley's species, of a number of brown horny plates with pigment in between, while in the present species they consist of two rings of small transparent plates round the central opening, then a ring of about six large brown plates, and then another moi'e or less complete ring of slightly smaller irregular brown plates, pigment granules being absent (fig. 2). The actual resemblances between the two forms are the relative shortness of the introvert and absence of hooks, the brown papiUae especially crowded on the introvert, the presence of only two retractors, and the diverticula on the contractile vessel. The differences, except as regards the body-papillae, are slight and obviously only differences of degree, and I give them in tabular form :- Ph. weldonii. Ph. gaudens. Longitudinal muscles 10-12, splitting Muscles 14, splitting in the middle of into two in the middle of the body, and the body, but into more than two, so that fusing at hind end. posteriorly there are as many as 3 4 ; not fusing at hind end. Opening of nephridia a little behind Opening of nephridia at anus level, anus- Retractors arise at a level between the Retractors arise at the level of the anterior two-thirds and the posterior middle of the body, one-third of the body. |
