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Show 1905.] AND ECHIURIDS OF THE " SKEAT " EXPEDITION. 39 III. Genus P hasco losom a. 8 . P hascolosom a p y r ifo r m is , sp. nov. (P la te II. fig. 3.) Loc. Pulau Bidan, Penang. Numerous specimens. The expanded animal is pyriform in shape, the introvert being considerably shorter than the body. The skin is thick, without papilla; when seen under the lens; in most of these specimens the colour is a dirty-white with a slight tinge of very pale green which may be due to the reagent. Some, however, are distinctly reddish-brown (i. e., a lightish copper), and in nearly all it is noticeable that the skin is covered with splashes of white, which just behind the tentacles are aggregated into a broad white ring. Internally the most peculiar character is that both anus and nephridia open on the introvert, the anus halfway between its base and the tentacles, the nephridia just in front of its base (v. fig. 3 a). The muscle-layers are continuous, and there are two broad and short retractors which arise within the middle third of the body and fuse directly they meet. The oesophagus, covered by a contractile vessel with numerous black-tipped diverticula, extends to the extreme hind end of the body (at which point the contractile vessel ceases), and then bends sharply forward dorsal to the intestine to enter the latter at the anterior end of the body ; in its anterior half this part of the oesophagus is held in place by three small muscles which converge to be inserted fairly close together in the mid-dorsal line. The intestine is much coiled and opens at the anus by means of a rather short rectum ; it is not held down to the hind end of the body, but is attached in front by means of the spindle muscle. The nephridia are about a quarter of the body-length, hardly pigmented, their anterior portion swollen. The papillate bodies consist of (a) a low circular papilla, with a wide central opening, on the external body-wall, (6) of the glandular portion, lying rather deep down below the cutis and epidermis, and (c) of a fairly long, more or less straight duct, leading to the external opening (y. figs. 3 b, 3 c). IV. G enus C lo eo sipho n . 9. C lo eos ipho n a sp e r g il lum Quatrefages. Selenka, tom. cit. p. 126. Loc. Pulau Bidan, Penang. One specimen. V. Genus A s p id o s ip h o x . 10. A sp id o s ip h o x ste en str u pii Diesing. Selenka, tom. cit. p. 116. Loc. Pulau Bidan, Penang. One specimen. |