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Show *>0° SIR C. ELIOT OX XUDIBRAXCHS [Doc. 1, 10. THORDISA STELLATA, sp. n. One specimen from Chuaka. The living animal was soft, but yet distinctly harsh to the touch. The colour is a yellowish grey with small sandy patches and also dull chocolate blotches, the latter at the mantle-edge and round the visceral mass. The underside is of a greyish white, with pronounced chocolate blotches round the foot, and a much fainter ring of the same halfway to the mantle-edge. The preserved specimen, which is much bent, is 2-8 centimetres broad, and would be at least 3 5 centimetres long if straightened out. The texture is rather leathery, but the back is covered with small soft papillae of various sizes and colours, and all simple. The rhinophore-openings are slightly raised, closed, and apparently crenulate. The branchial pocket is slightly raised, stellate, and entirely closed by six lobes. The branchiae are yellow, tripinnate, five or six in number according as one much smaller than the others is reckoned separately or as an appendage. The rhachis is very thick and broad. The foot is grooved and notched in front. The tentacles are close together above the mouth and somewhat flattened. N o labial armature could be found. The radula consists of 36 rows, each containing about 70 hamate teeth of the ordinary type. The innermost are smaller and the outermost less distinctly formed, but neither rudimentary nor denticulate. No genital armature was discoverable. This specimen appears referable to Thordisa and bears a strong resemblance to T. villosa, but differs in the more leathery consistency, the stellate branchial opening, and the outermost teeth of the radula. 11. THORDISA CROSSLAXDI, sp. n. (Plate XXXII. fig. 3 & Plate X X X I I I . figs. 4-8.) Many specimens of this form were captured at Chuaka, on the East Coast of Zanzibar, in 1901-02. The animals are large, the measurements of a fine alcoholic specimen being, length 12-5 centimetres, breadth 9*1, height 2-5. The shape is therefore flat and oval. The coloration is in its general effect inconspicuous. The upper surface is sandy with blotches of brown irregularly bordered with black. The under surface (PI. X X X I I I . fig. 3) is whitish with numerous brownish spots and a brownish border. But when the upper surface is carefully examined it presents a great variety of shades of light and dark brown which cannot be easily described or depicted. The back is covered with thick-set pointed papillae, some of which are developed into distinct filaments at their extremities. The general texture is soft. The openings for the rhinophores and branchiae are slightly raised, and may be described as tuberculate since they open among tubercles, but they do not appear to be provided with special tubercles. The branchial pocket is an irregular oval and not stellate or crenulate. The branchiae (PI. XXXIII. fig. 5) are six in number and tripinnate. The |