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Show 1903.] FROM EAST AFRICA AND ZANZIBAR. 363 whereas in A. africana it is violet, both externally and in the intestines; (2) the tentacles are small; (3) there are no tubercles on the underside of the mantle-edge ; (4) the rhinophores and their pockets are somewhat different from those of A. africana ; (5) so are the teeth. It is possible that this is the Doris rusticana of Alder & Hancock ("Notes on a Collection of Nudibranchiate Mollusca made in India," Tr. Z. S. iii. p. 120), but in view of their statement " N o oral tentacles (?); the head with lateral angles ; branchial plumes five," identification is nob possible. 3. STAURODORIS DEPRESSA, sp. n. One specimen from Wasin. No notes as to living animal. The alcoholic specimen is 6-3 centimetres long and 4-9 broad. The general shape is broad and flat. The thick and fleshy mantle-briin is 2 centimetres wide, and the foot consequently unusually small compared with the dorsal surface, being only 2"7 m m . long and about 8 m m . broad. The colour is a uniform greyish white, with a slight tinge of violet anteriorly and down the middle of the back. The whole upper surface is covered with warts, which are small at the mantle-edge but increase in size towards the centre. The top of the larger ones, which measure 5 millimetres across, is flat and hard, consisting of a mass of densely-crowded spicules, and is of a somewhat different shade from the rest and in life possibly distinctly coloured. On the underside of the mantle-edge are numerous small tubercles of glandular appearance. The openings of the rhinophores and branchiae are tuberculate. The latter, orifice is indistinctly stellate and also indistinctly bilabiate, but it is not clear what its original shape may have been. Both the branchial and rhinophorial orifices are closed in the alcoholic specimen. The branchiae are six in number, but the hindermost pair are deeply bifid so that there appear to be eight. They are mostly bipinnate and rather scanty. The foot is grooved and notched in front. The tentacles are large, distinct, and somewhat flattened, with rather uncertain traces of a groove. There is no labial armature. The radula is broad and white, the formula being about 70.0.70x32. The teeth are simply hamate and all of much the same size. On some of the inner ones I was able to see eight or ten very minute denticles on the inside of the hook. This extremely fine serrula-tion is difficult to detect, but I expect that it is present on all the teeth except the outermost. The stomach is not free, but is enclosed in the liver. The female reproductive organs are armed with small transparent brick-like scales. This form offers analogies to both Homoiodoris and Artachcea Bergh, particularly the latter, and the thick leathery mantle and large warts also remind one of Asteronotus. O n the whole I class it though very doubtfully, as Staurodoris, mainly because the openings of the rhinophores and branchise are closed by the surrounding tubercles. |
