1903.] PROM EAST AFRICA AND ZANZIBAR. 381 



either side of the rhachis ; the innermost are smaller, the two or 

 three outermost degraded and sometimes bifid. The vestibulum 

 genitale, like the rest of the body, is full of rod-shaped spicules, 

 but no armature could be discovered in the ducts. 



I think this is undoubtedly the animal described by Kelaart 

 {I. c. p. 298) and said to resemble a piece of bone or worm-eaten 

 white stone. It is also not unlike Alder and Hancock's plate 

 {I. c. xxviii. figs. 9 & 10). But their description does not entirely 

 correspond with my specimens, particularly in speaking of the 

 branchial pocket as " a cup, the margin of which is scalloped and 

 produced into a large lobe in front." Kelaart, on the other hand, 

 says there are four or five branchial plumes which emerge hori- 

 zontally from under the posterior termination of the dorsal ridge, 

 which is correct. The branchiae seem to be somewhat variable in 

 number, and, as is often the case with Dorids, admit of being 

 counted in more than one way. 



26. SCLERODORIS TUBERCULATA, Sp. 11. 



One specimen from Prison Island, Zanzibar Hai'bour. 

 The following notes were made on the living animal : — " Dark 

 brown with sandy spots, exactly like a sponge splashed with sand. 

 Underside clear bright brownish red. Branchial pocket crenu- 

 late. The middle part of back covered with conical warts, which 

 form an irregular keel ; smaller warts on mantle-edge. Rhino- 

 phores red ; branchiee eight, voluminous ; axes red, tips white. 

 Animal alters shape, sometimes rather high, sometimes quite flat 

 like Platydoris. Consistency quite hard and rather rough, _ Two 

 depressions with deep black markings as in some species of 

 Trijjpa." The alcoholic specimen bears a strong general resem- 

 blance to Trifp-pa areolata, but is stiff and spiculose like Platydoris, 

 and has nothing of the flabby gelatinous feeling which charac- 

 terises T. areolata. The back is covered with irregular tubercles, 

 simple and compound, of all shapes and sizes, all granulate and 

 sometimes connected by ridges so as to form a reticulation. There 

 is an indistinct median ridge and two large pits with black 

 bottoms, one in front of the branchial pocket and one about half- 

 way up on the right-hand side. The general colour is greenish grey. 

 The length is 6-5 centimetres, the breadth 4-2, and the height 2-2, 

 The oral tentacles are distinct, digitate, and white. _ The foot is 

 grooved and notched in front, the upper lamina being attached 

 to the head below the mouth. The labial cuticle is strong and 

 puckered, but no armature was discovered nor any ptyaline glands 

 as in Trippa areolata. The radula consists of 40 rows, containing 

 about 50 teeth on each side of the rhachis. These teeth are white 

 and simply hamate ; the innermost are smaller than the rest, the 

 two or three outermost degraded and often bifid. The stomach is 

 free and laminated internally. No genital armature was discernible. 

 The rhinophore-pockets are raised and provided with nine valve- 

 like tubercles, of which two are much larger than the others. 

 The rhinophores are short and thick, with about 50 perfoliations. 

 The branchial pocket is entirely closed by ten valve-like tubercles, 



