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Show 1904.] FROM EAST AFRICA AXD ZANZIBAR. 391 of small dots, and not collected into large spots. But it is possible that the buccal parts of Chr. splendida, respecting which we have no information, may present specific differences, and identification is therefore at present not warranted. 6. CHROMODORIS TRYOXI (Gar.) var. (= Chr. aureo-purpurea Collingwood). [See Bergh, " Neue Nacktschnecken, No. iv.," Jour. Mus. Godeffroy, Heft xiv. p. 14 ff.] Two specimens from Chuaka, the larger of which was about three inches long in life. The body was quite smooth and very soft. The mantle and edge of foot bordered with light violet; the back translucent, allowing a rough, broad, net-like grey pattern to be seen beneath the surface ; the whole surface covered with opaque spots of bright orange-yellow. Foot broad and deep, with white sides bearing orange-yellow spots. The rhinophores with purple lamellae and a longitudinal white stripe behind. The simply pinnate branchiae white, with a deep purple stripe down each edge *. Tbe animal was lively in its movements, and the branchiae continually waved with a quick vigorous motion from side to side. The alcoholic specimen is 35 m m . long, 13 broad, and 15 high, stoutly built, with a narrow mantle-edge of only 3 mm., and the tail projecting 8 m m . behind. The edges of the rhinophore and branchial pockets are slightly raised. The branchiae seem to be 27 in number, the median anterior plume being the largest. The circuit is interrupted behind, and the ends of the row of plumes turned inwards in a spiral. Several of the plumes are bifid at the tip. The anterior- margin of the foot is slightly grooved but not notched. The labial tentacles are very small and set somewhat above the mouth. The lips are large. The labial armature consists of two strong, rough plates composed of a closely-compacted mass of small thick hooks. The long white radula has 96 rows of colourless teeth, containing about 50 teeth on each side of the rhachis, which exhibits folds and puckers. The teeth have the characters usual in the genus; the innermost bear four denticles on both sides, the others five large and distinct denticles below the terminal hook on the outermost side only, the highest being the largest. In the outermost the denticles move upwards, till they are all on the apex of the teeth. The form of the teeth and labial armature is accurately represented in Bergh's plates. I think this form may be safely identified with Chr. tryoni. It differs from Bergh's description only in the absence of ocelli with black centres. It appears to be also identical with Collingwood's Chr. aureo-purpurea, though the latter is said to have only 10 branchiae. The two varieties may be described as Chr. tryoni var. ocellata and var. aureo-purpurea. * f I quote from the notes on tbe living animal, but must admit that this expression is obscure. (Outer and inner sides, parallel with blood-vessels shown in fig. 3,. PI. XXIII.-C. C.) |
