1903.] T'-ROM EAST AFinCA AND ZANZlllAR. 38.1 



firm and fleshy, with something of tlie i-ough feeling cliaiaeteristic 

 of Platydoris. 



The alcoholic specimen is dirty white in colour with greyish 

 blotches. The measurements ai-e : length 5*5 centimetres, breadth 

 2'7, height 2"6. It will therefore be seen that the shape is very 

 distinctly arched. In the middle of the minutely granulated 

 back is an indistinct keel from which extends on either side a low 

 fleshy reticulation. Independent of this reticvilation, and some- 

 times concealing it, are a number of excrescences which, even in the 

 alcoholic specimen, present the most extraordinary resemblance 

 to the miscellaneous growths and accretions found on old shells 

 and sponges. Some are as much as 4 millimetres high. I en- 

 deavoured to pull them oft", being sure they could not be part of 

 the mantle. They are so, however, and afibrd an even more 

 remarkable case of mimicry than Trijypa areolata. The edges of 

 the rhinophoi-e- and gill-pockets are crenulate, but not raised. 

 The eight tripinnate branchi* are deeply retracted into the 

 bottom of the pocket. The anal papilla is large and has a cleft 

 down the posterior side which appears natural. In the alcoholic 

 specimen the foot is narrow with the edges tvirned inwards, but 

 it was probably fairly broad in life : it bears a shallow groove in 

 front, the upper lip of which is notched. The tentacles are very 

 small and digitate. The blood-gland is large, reddish, and double : 

 the central nervous system in a reddish capsule and much con- 

 centrated. There is no labial armature. The radula, which is 

 large and wide, consists of 42 rows, containing about 55 large 

 blunt hamate teeth on each side of the rhachis : the innermost 

 are smaller than the others, and one or two of the outei'most are 

 also smaller and distinctly bifid. The reproductive system is 

 unarmed. 



29. ScLERODORis coRiACEA, sp. n. (Plate XXXIY. figs. 3 &■ 4.) 



One specimen from a cave near Chuaka on the East Coast of 

 Zanzibar. 



The living animal was yellowish brown in colour above and 

 light orange undeineath. The pi-eserved specimen is 2'4 centi- 

 Hietres long, 1-7 broad, and '8 high in the middle of the back, 

 the sides of the mantle being very low. The foot is large, 

 being 1'9 centimetres long and I'l broad : the sides are developed 

 into wide and very thin expansions. The anterior margin is 

 deeply grooved, but the upper lip is not split though it is indented. 

 The rhinophoi-e-openings have somewhat raised and indistinctly 

 crenulate edges. The branchial pocket is wide, conspicuous, and 

 somewhat two-lipped in shape. The edge is turned outwards and 

 is not at all crenulate. The branchia> are six and tripinnate. 

 The general texture of the animal is leathery, and the whole 

 dorsal surface is covered with a distinctly raised but somewhat 

 irregular i^eticulate pattern. Both this pattern and the gi-ound 

 suiface are granulate. The buccal tentacles are long, thin, and 

 pointed. There is no labial armature. The radula consists of 

 40 rows, witli about 40 teeth on each side of the naked rhachis. 



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