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Show 94 SIR C. ELIOT ON NUDIBRANCHS [May 17/ lation of the jaw varies with age. Of the six species, M. pellucida seems distinct from the others, which are all nearly related to M. arborescens. M. levis is distinguished by being quite smooth and not at all tuberculate. M. rcimosa is closely allied to M. arborescens, and differs chiefly in having unusually large branchiae and appendages. M. viridescens and albo-tuberculata differ from these last two forms in having branched processes on the velum, and are closely allied one to another in structure, though by no means similar in external appearance. It is noticeable that in none of these forms is the interior of the buccal cavity black, and that most of them have only one fully-developed row of denticles on the jaw. M a r io n ia p e l l u c id a , sp. n. One specimen dredged in 10 fathoms near Wasin, East Africa. The living animal showed very little colour but for the pink liver which shone through the transparent integuments. The back was sparsely reticulated with vermilion, turning to deep crimson near the bases of the branchiae, and also bore some opaque white raised spots. The sides of the body were white and the edge of the velum sandy-coloured. The velum was not bifid, and bore 12 processes, of which 8 were 3-branched. The branchiae were 13, of moderate size, directed backwards. The finer branches very delicate and transparent. The alcoholic specimen is yellow, with small tubercles of a lighter colour on the back and* sides. It is 15 millimetres long, 5 broad at most, and 4 high. The 13 branchiae are rather far apart from each other; none are large, and the first pair as well as the last three are minute. The dorsal margin is not very prominent. The rhinophores are large. The velum as described above, but though the outermost processes probably represent the tentacles, they do not seem to be grooved as usual. The long narrow jaws bear three or four rows of denticles on the edge. The radula is at most 22 +1.1.1 +22 X 25, but many of the rows are much shorter. The central tooth is not very wide and tricuspid, the side cusps being as high as that in the middle. The stomach has a circular band of about 70 small yellowish plates, all of much the same size and usual triangular shape. M a r io n ia l e v is , sp. n. (Flate IY. fig. 4.) Six specimens from Ohuaka, East Coast of Zanzibar, and Wasin, East Africa. Two were dissected. The living animals were high and narrow in shape, with a fiat back. The sides were described as white, mottled with translucent patches. The ground-colour of the back was a light purplish brown, with stripes of the same colour but darker and others of white. The branchiae and rhinophores were pink with dark red blotches. An uninjured alcoholic specimen is 26 millimetres long, 10 high, |
