1903.] FROM EAST AFRICA AND ZANZIBAR. 373 



numerous black lines instead of valleys. The tentacles are knob- 

 like but large and distinct. The rhinophore-openings are quite 

 smooth, whitish yellow, and fairly large ; they are flattened, but 

 look as if they had once projected. The branchial pocket is fairly 

 large, quite smooth, and whitish yellow. The rim is thin but 

 projects amply. The direction of the opening is posterior, not 

 vertical. The branchiae (as shown in the figure) consist really of 

 two plumes arising one on each side of the anal papilla, but each 

 is split into three subdivisions, so that there appear to be six. 

 They are scanty and iiregular ; mostly bipinnate, but partly ti-i- 

 pinnate. The buccal parts are protruded and are yellowish white 

 with black spots. There is no trace of labial armature. The 

 radula consists of whitish and simply hamate teeth ; the outer- 

 most are not denticulate or degraded ; the innermost ai'e smaller 

 and more crowded than the othei-s. On the left side under the 

 mantle is a curious gland-like projection, which is perhaps merely 

 a blister caused by alcohol. On the right side in the usual place 

 is a large yellow lump with black spots on which ai-e placed the 

 genital orifices ; they are suri-ounded by strong folds, but no 

 armature was discoverable in the organs themselves. 

 I propose to call this species Hcdgerda vjilleyi. 



16. Halgerda wasinensis*, sp. n. (Plate XXXIV. figs. 1 & 2.) 



Three specimens captured by Mr. Crossland at Wasin Island, 

 East Africa. 



They difier from R. formosa and H. loilleyi in having not only a 

 pattern formed of ridges on the back, but also distinct knobs at the 

 points where the lines of this pattern join one another. 



In the living animal (PI. XXXIY. fig. 1) the mantle-edge was 

 white, bvit the ground-colour was a dull red-brown ; nvimerous 

 brown spots of a deeper colour were arranged round the mantle- 

 edge and a few scattered over the central dorsal area. Over the 

 whole dorsal sm-face was a raised pattern in brilliant orange. The 

 white foot was also spotted with deep reddish brown. This colour 

 also appeared on the rhinophores in broad bands alternating with 

 white, and in broad lines on the rhachis of the white gills. The 

 foot projected behind the mantle in crawling. 



The largest alcoholic specimen is 1*9 centimetres long, 1-2 broad, 

 and "7 high ; the contracted foot is 1*4 long and -4 broad. Traces 

 of the original colour remain, but the yellow has mostly disappeai-ed. 

 The raised network starts fi'om a central lidge and is developed in 

 a pattern composed of I'oughly triangular spaces. The foot is 

 1-2 centimetres long and only 3 millimetres broad; the tail is 

 5 millimetres long. The anterior margin of the foot is grooved 

 and the upper lip notched. No oral tentacles are visible, but in 

 all the specimens the head is so contracted that it would be unsafe 

 to say none exist in life. The rhinophore-openings are set in a 

 tubercle and are very diilicult to see. The rhinophores are long, 

 but only a small part is lamellate. The biunchial pocket is quite 



* This name is wrongly spelt " wassinensis " on Plate. 



