378 SIR C. ELIOT ON XUDIBRAXCHS [DeC. 1, 



mottlings round the foot. The rhinophores were dark brown 

 with white lamellse ; the branchiae sandy-coloured. The animals 

 were very stiff and harsh to the touch. 



The larger alcoholic specimen is 3-8 centimetres long, and 

 broader behind than in front, the maximum breadth being 2-2. 

 The whole dorsal surface is covered with extremely minute 

 granulations, which can only be seen under a strong lens. The 

 rhinophore- pockets are very slightly raised and crenulate. The 

 branchial pocket is stellate, with six not very distinct lobes ; the 

 branchiae are six, tiipinnate, small and deeply retracted. The 

 anterior end of the foot grooved and notched as usual ; the oral 

 tentacles distinct, white and conical. The labial cuticle is 

 strengthened by some minute rods, but they are not combined into 

 a plate or rim. The radula consists of 36 rows, containing about 

 50 teeth on each side of the rhachis. The innermost and outer- 

 most teeth are smaller, the two or three outermost degraded but 

 not denticulate. The male branch of the reproductive organs is 

 armed with colourless scales, bearing erect spines, not hooks. The 

 female branch has strong folds. 



23. Platydoris incerta, sp. n. 



Seven specimens, found on brown sponges at low tide, Prison 

 Island, Zanzibar. 



The largest of the living animals was about an inch and a half 

 long. They were ail very flat in shape, sluggish, strongly adherent, 

 and, though smooth, of the stiff coarse texture characteristic of 

 the genus. The coloration rendered the animal invisible on the 

 sponge, but was somewhat variable. As a rule it was yellowish 

 brown, but one specimen was tinged with red and another with 

 green. On the dorsal surface were collections of minute sandy 

 dots, which in some specimens formed a line down the middle of 

 the back. The underside was lighter in colour and without 

 markings. The rhinophores were tipped with white, the gills 

 brown or sandy. 



The alcoholic specimens are all of a uniform dirty yellow. The 

 measurements of the largest are : length 1-6 centimetres, 

 breadth 0-9, height 0*4 ; the foot is 1*5 long and 07 broad. The 

 rhinophore-pockets are crenulate, in some specimens slightly 

 raised, in others closed and almost flat. The rhinophores have an 

 unusually long stalk bearing a thick bunch of perfoliations, out of 

 which rises a narrow bare tip slightly bent backwards. The 

 gill-pocket is rather indistinctly stellate, with about six lobes, and 

 contains six somewhat small bipinnate branchiae. The foot is 

 grooved in front and the upper lamina notched. The tentacles 

 are narrow and digitate. There is no trace of labial armature. 

 The radula formula is about 35.0.35 x 60. The teeth are white 

 and simply hamate, of a rather thick and clumsy shape; the 

 innermost are smaller but formed like the rest, the two or three 

 outermost are degraded. The reproductive organs appear to be 

 immature, but both the penis and A-agina are armed with trans- 

 parent, colourless, brick-like scales, apparently arranged in four 



