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Show 1 9 0 4 .] FROM EAST AFRICA AND ZANZIBAR. 2 6 9 - but if they are noticed at all it seems simpler to give them a specific name, M ad r e l l a fer r u g in o sa . In the plates of Madrella ferruginosa in the first of these papers (P. Z. S. 1902, vol. ii. pi. vi. fig. 6) the central cusp of the median tooth is represented as much too blunt, and I now give a new figure of it (cf. PI. XVII. fig. 9). It is really long and rather pointed. This character is quite clear in the hinder part of the radula, but in the front part it would appear that the end of the central cusp becomes broken or worn off and the point looks blunt as in the first figure above referred to. O rodoris. [Bergh, Jour. d. Mus. Godefiroy, Heft viii. 1875, pp. 67-71.] O rodoris s tr ia ta , sp. n. One specimen from Pemba found on the shore crawling among' Ulva. The description of the living animal is as follows :-" Six inches long. The ground-colour of the back is greenish centrally and deep green and chocolate laterally. The mantle-edge has a wide border half an inch wide. The most characteristic external feature is the presence of numerous prominent, narrow ridges running over the back. The back also bears fairly large tubercles over which these ridges continue. There are three circular areas on each side of a deep green colour where the ridges are absent. The ridges are usually white, but in places are tinged with greenish grey. The rhinophores are vertical, the pockets a little raised at the edges. The gills are 8, fairly large, having a fluffy appearance, but not very sensitive. The anal papilla and main rhachis of the gills are pink. The secondary branches are light brown and the smaller branches white. The gill-pocket is irregularly lobed. The mantle-edge is soft but stiff in texture, and may assume a very wavy outline. The under side of the animal is white, with a narrow, irregular, brownish line near the junction of the mantle and the foot." The preserved specimen has suffered severely from contraction,, and most of the internal organs except the buccal mass have been lost through a rent in the side. The actual length and breadth are 71 and 59 mm., but could be increased by at least a centimetre each if the animal were straightened out. The unusually strong and fleshy mantle-edge is 9 mm. thick. The colour is a uniform yellowish white. The characteristic curved ridges are still plainly visible, but the tubercles are somewhat obscured; there seem to be four between the rhinophores and branchiae and one behind the branchiae : two can be distinguished on each side. The pockets of the rhinophores are 4 mm. high. The gill-pocket is raised and bears 8 irregular lobes. The 8 branchiae are strong, with broad stems, and mostly quadripinnate. The anal papilla is large, crenulate, and connected with one of the anterior gills by a |
