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Show !904.] FROM EAST AFRICA AND ZANZIBAR. 387 next to the rhachis bear 3-4 small denticles on each side, and those nearest to them are somewhat similar but denticulate only on the outer side; the others are long and hamate, with about 8 denticles on the outer side (PI. XXIII. fig. 4, a, b, c). The outermost bear 3-4 denticles on the apex. A drawing of the alimentary canal is annexed (PL XXIII. fig. 5). I think these animals can be referred to Chr. reticulata Pease, with which Collingwood's Chr. alderi seems to be identical. All my specimens are flat, with ample mantle-margins, and this agrees with Collingwood's description and plate. Bergh, on the contrary, says: " I)ie Korperform ist langlich nicht sehr nieder-gedruckt . . . der Mantelsaum ziemlicb schmal." But these soft Chromodorids have great powers of changing their shape and proportions. The branchiae are much more numerous than in the specimens previously described, but a multiplication of the small plumes in the spiral does not appear to constitute a specific difference. 2. CHROMODORIS SYKESI. (Plate XXIII. fig. 6.) Chromodoris sykesi Eliot, Abstr. P. Z. S. 1904, No. 4, p. 15, March 8. Numerous specimens from the East Coast of Zanzibar, obtained both on the shore and by dredging. A few of the animals were of a reddish brown with dirty yellow markings, but in the majority the coloration was most gorgeous (PI. XXIII. fig. 6). The dorsal surface was bright orange, passing into light yellow towards the edge of the mantle, round which was a double border of reddish brown internally and bright violet externally. On the back were numerous rings of opaque white, but otherwise the whole body was translucent. The foot and underside of mantle were of a rich light yellow. The rhinophores and branchiae were both of a deep brown-red with opaque white spots. The per-foliations of the rhinophores were indistinct, and the pinna? of the branchiae small though made conspicuous by white lines drawn along them. The animal was rather flat and very soft. The mantle was very ample. The largest alcoholic specimen is 40 mm. long, 27 broad, and 10 high. The free edge of the mantle measures 7 m m . over the head, 10 at the sides of the body, and 13 over the tail. In giving the measurements, the breadth of the body is estimated as the mantle falls in its normal position: the edge of the mantle is taken as extended, but not stretched unnaturally. The openings of the rhinophores and branchiae are small and only slightly raised, but the interior of the branchial pocket is a capacious and very strong bag. The branchiae are arranged as in Chr. reticulata and vary from 12 to 18, according to the size of the spiral. They are red and striped with white. The anal papilla is tall, red and spotted with white. The foot is rounded and grooved in front. Two rather strong folds connect the upper lamina with the corners of the mouth. The oral tentacles were not distinctly PROC ZOOL. Soc- 1904, VOL. I. No. XXVI. 26 |