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Show 1904.] FROM EAST AFRICA AND ZANZIBAR. 403 SPHCERODORIS L^EVIS, var. VARIEGATA. [Bergh in Semper's Reisen, Heft xvii. p. 924, 1890.] One specimen from Mnemba on the East Coast of Zanzibar, found in the act of laying a ribbon of light violet-coloured eggs. The body of the living animal was described as firm and shiny, dark brown in colour above, with greenish and sandy patches ; the underside was a lighter shade of uniform brown. The alcoholic specimen is 31 m m . long, 20 broad, and 14 high. The foot, which is nearly as large as the body, is 28 m m . long and 15 broad. The colour is mottled-brown of darker and lighter shades. There are also bands formed of minute black spots, not very conspicuous, and arranged in an irregular pattern, particularly in the neighbourhood of the branchial opening. Though the dorsal surface cannot be described as either tuberculate or papillose, it is not, strictly speaking, smooth, but bears low irregular excrescences which resemble a marine growth. Also, there are about 10 shallow pits (? glandular) distributed at irregular intervals round the mantle-edge. Like the bands, they are inconspicuous, about 1 millimetre wide, with slightly raised edges and a black centre. The edges of the rhinophore and branchial pockets are not much raised and entire. There are 14 small but stout, simply pinnate gills, set in a circle which is slightly open posteriorly. The head is joined to the upper lamina of the foot at the sides, and there are no distinct tentacles, though two small prominences by the mouth may represent these. There is a very narrow but strong labial armature, composed of minute hooks. The radula is rather narrow, with a wide naked rhachis. There are about 70 rows, each containing about 25 teeth on either side of the centre, but the teeth mostly point towards the rhachis, and the whole arrangement is very irregular so that the usual radula formula hardly meets the case. The teeth present the form characteristic of the genus, but the innermost are somewhat wider than Bergh's figures of S. Icevis (I. c. pi. lxxxviii.) and bear 7 or 8 denticles. The denticles on all the teeth are extremely delicate and fine. There is no stomach apart from the hepatic mass. The reproductive apparatus is unarmed. This form is clearly a Sphcerodoris (as shown by the buccal parts, head, and branchiae), and, equally clearly, neither S. punctata, papillata, nor verrucosa. It undoubtedly comes very near to S. Icevis, of which I provisionally describe it as a variety, but it varies somewhat from the type specimen described by Bergh both in the pits, which he does not mention, and in the teeth, and may prove to be a new species. I have also examined several individuals, apparently referable to S. Icevis, captured by the Skeat Expedition at Pulau Bidang near the Malay Peninsula. Their dentition is like that described above, and they have a few (in one specimen only two) pits, but the back is quite smooth and of an almost uniform bluish-ohve colour. PROC. ZOOL. Soc-1904, VOL. I. No. XXVII. 27 |
