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Show 386 SIR C. ELIOT ON NUDIBRANCHB [Mar. 1, Europe is not found north of the Mediterranean. In the Pacific it extends to Japan and Puget Sound. 1. CHROMODORIS RETICULATA Pease. (Plate XXIII. figs. 1-5.) [See Bergh, "Neue Nacktschnecken, No. iv.," Jour. Mus. Godeffroy, Heft xiv. p. 9 ff.] Four specimens, found at different times on both the East and West Coasts of Zanzibar at low tide. The colour and size vary considerably. The following is the description of one living specimen:-" 23 millimetres long, 12 wide. Foot narrow, with the sides crinkled. Mantle-edge fairly ample and undulated. The whole animal very soft and almost gelatinous. The dorsal surface whitish, with numerous red reticulations, which became closer at the edge and formed a. red border. Outside this was a yellow border, passing over to the underside. The rhinophore and branchial openings were not raised. The rhinophores were crimson-lake, with fine white lines on the perfoliations. The branchiae were of a transparent light pink, with two lines of crimson-lake down the main axis. The under surface of the animal was of a beautiful opaque white. The foot projected behind the mantle." Another specimen (67 millimetres long and 30 broad) was described as much lighter than that just noticed, but having similar lines and reticulations ; there was no crimson-lake and no red border ; all the red and yellow markings were bright and light. It was infested with violet-coloured copepoda. On the other hand, two other specimens were of a much darker colour. The general effect was reddish brown, due to a close reticulation of that shade on a dirty-white ground. The mantle-border was a dark reddish orange. The gills were of a very deep colour, and in one specimen almost black. The pinnae were so thick and swollen that until closely examined each plume appeared to be a simple column. The alcoholic specimens are flat, smooth, and very soft. The branchial openings are fairly large, but in the living animal were capable of contracting and almost closing. The branchiae are 22 to 24 in number, set in an incomplete circle with the ends turned inwards in a spiral (PI. XXIII. figs. 2 & 3). The front plumes are long and slender, while those behind in the spiral are very small. Hence on a superficial examination only 10 or 12 are visible. The foot is rounded and grooved anteriorly, and the upper lamina is connected with the sides of the mouth (PI. XXIII. fig. 1). Near the points of junction appear to be two indistinct retracted tentacles. The labial armature is a dense mass of long rods, slightly curved and bifid at the end. On the rhachis of the radula * are transparent lozenge-shaped thickenings. The innermost teeth * Only one preparation of the radula has been preserved from one of the darker specimens. |