1904.] FROM EAST AFRICA AXD ZANZIBAR. 295 



sides were folded over the body, but 23 when they were extended. 

 The ground-colour was mainly whitish, but on the dorsal surface 

 this was almost entirely hidden by the numerous dark green 

 branchial ridges. The outer surface of the lateral expansions was 

 sandy coloured with darker spots, and on the foot were many 

 irregularly- arranged deep black spots. Along the junction of the 

 lateral expansions and the foot ran a line of violet rings, and 

 there were four or five more on the forehead. The inside of the 

 furrowed rhinophores was violet, as was also the end of the body. 

 The animal secreted a very abundant mucus. 



In the preserved specimen the branchial ridges are very large 

 and distinct, being as much as 1*5 mm. high. There are about 

 36 main folds, and smaller ones in between. The buccal mass is 

 small, only about 1'5 mm. long, and the crop half that length. The 

 teeth are exactly as figured by Bergh, with about 12 denticles on 

 the margin, but are less numerous than in his specimens. In the 

 radula I found 15 and 14 respectively, and in the heap at the 

 bottom about 40 and 50. 



Two pencil di-awings by Mr. Crossland are reproduced because 

 they show the animal in a somewhat different attitude from that 

 in which it is ordinarily represented. 



Elysia faustula, B. 



[B. in S. R. iv. pp. 186-190.] 



One specimen from Wasin, East Africa. 



There are unfortunately no notes on the living animal. 



The preserved specimen is very flat and crinkled, surprisingly 

 like a planarian in appearance, and also somev/hat resembling 

 Tridachia, but the wings show no signs of being Joined behind 

 the neck. The length is 19 and the breadth 16 mm., but the 

 form has become somewhat contorted, and these measurements 

 represent at least 25 and 20 if it were straightened out. The 

 colour is a uniform pale yellowish grey, with a very distinct deep 

 black border all round the edge, and a few scattered black dots on 

 both the upper and lower surface. There are three black dots 

 on the peiicardial prominence, and the anterior margins of the 

 tentacular groove are black. There is a fine furrow dividing the 

 foot transversely just below the point where the wings arise, 

 behind which the foot is not clearly difierentiated from the sides 

 of the body. The anterior margin of the foot is not expanded 

 into tentacular processes. From the rather large pericardial 

 prominence issue three vein-like ridges on each side. The two 

 anterior pairs a,re simple and have only very slight ramifications 

 near the edge of the wings. The third pair soon divides into three 

 main branches, which have one or two secondary ramifications. 

 The tentacles are rather large and broadly opened. 



The radula consists of 17 teeth, besides which there is a heap of 

 about ten disused ones. The shape is exactly that given in Bergh's 

 plates (in S. R. iv. pi. xxii. figs. 15-17), elongate, and with no 

 trace of denticulations. 



I think this specimen may be certainly referred to E. faustula B., 



