1904.] FRUM EAST AFRICA AND ZANZIBAR. 393 



outside and white inside, as had also the foot. In the middle of 

 the back were two longitudinal white lines uniting behind the 

 branchiae ; on the tail, which projected well behind the mantle, 

 was one white line. The gills and rhinophores were yellow, and 

 the slightly raised pockets of both were fringed with the same 

 colour. The creeping-surface of the foot was narrow. The sides 

 of the body were black with a white stripe between the mantle 

 and the foot. 



The alcoholic specimens are high and stout, with the colours 

 fairly well preserved. The largest is 26 mm. long, 13 broad, and 

 10 high. The mantle-margin is fairly ample, measuring about 

 3 mm. at the sides and head, 5 mm. over the tail. Of the 

 branchial plumes there is only one which can be called simply 

 pinnate in the strict sense, all the rest being more or less 

 bipinnate. Some are merely bifid, and some bear four or five 

 branches. It is rather difficult to say what is the number, as 

 when a small plume springs up at the base of a large one it may 

 be counted either as an accessory bianch or as a sepai-ate branchia, 

 but they may perhaps be desci'ibed as 10, set in a semicircle. The 

 foot is grooved and notched in front ; the tentacles are close together 

 above the mouth, conical and larger than usual in the genus. The 

 labial armature is greyish and formed of a thick mass of bent rods, 

 some bifid but most simple. The formula of the radvila is in one 

 specimen 94 X 90.0.90 and in the other 90 x 75.0.75. The inner- 

 most teeth bear three denticles on both sides ; the remainder 3-4 

 minute denticulations on the outer side only, and some are quite 

 smooth and simply hamate. 



I think these specimens may be referred to Bergh's Chr. eliza- 

 hethina (S. R. xi. pp. 466-473). The difference in appearance, 

 though striking, is due to the relative preponderance of black in 

 one and of white in the other variety. The dentition and the 

 tendency to bipinnate branchi?e are strong points of resemblance. 

 On the other hand, the difiei-ences found in both the African 

 specimens are sufficient to constitute a well-marked variety. 



(1) Whereas the specimens from the Philippines are whitish 

 with black stripes, these are black with white and yellow stripes. 



(2) The denticles on the teeth of the African specimens are fewer 

 and finer and many of the teeth ai-e smooth. 



9, Chromodoris ruxcinata B. 

 [Bergh, in S. R. xi. pp. 479-481.] 



0ne*6pecimen from Chuaka on the East Coas-t of Zanzibar.. 



The general colour of the living animal was light blue witb 

 many spots, some dark blue and some whitish yellow, on the back, 

 tail, and sides, but not on the foot. Some of the yellow spots 

 were arranged so as to form a rather irregular border at the sides 

 of the mantle and a line down the middle of the back. The 

 rhinophores and axes of the gills were a bright, light red. The 

 gills were kept in motion. 



[15] 



