256 SIR CHARLES ELIOT ON NUDIBRANCHS [Mar. 17, 



vivid crimson-lake. The l)Ocly of the rhinophores is brown and 

 inconspicuous, but the tips are whitish and have a crimson ring. 

 Although the colour of tiie animal when analysed is as described, 

 the general effect in most lights is that it is puiple with a silveiy 

 glaze. 



The specimens were active in their movements, and in particular 

 the long oi'al tentacles were very mobile. The anterior margin of 

 the foot was produced into two deeply-grooved pi'ocesses, and its 

 sides projected in two laminaj along the whole length of the body. 

 The cerata, which were not at all caducous, were set on fan-like 

 projections of the dorsal margin, from 13 to 20 in number, on 

 each of which weie from 10 to 20 cei-ata. The largest individual 

 appeared to have about 640 cerata in all. None of the cei-ata were 

 large, but they became more crowded and smaller towards the end 

 of the body, where they extended to the tip of the tail. In three 

 of the presei-ved specimens theie was a veiy distinct raised border 

 on each side of the back, connecting the fan-like projections, and 

 almost resembling the mantle-edge of Dorids ; but in the fourth 

 this I'emarkable charactei" was not visible. Tlie oral tentacles were 

 very large and long ; the rhinophores, which stand between the 

 first clumps of cerata, weie small and lamellated, except the tips, 

 which were nariow and smooth. In the individual dissected the 

 radula consisted of a single series of 18 yellowish teeth. The 

 separate teeth were much as represented in Bergh's plate (l. c. 

 pi. iii. figs. 5, 6, 7), but somewhat more regular in shape, having 

 nine denticles very symmetrically arranged on each side of a 

 central cusp, but not taking the form of indentations of the cusp 

 itself. The cutting-edge of the jaw bore a row of fine but very 

 distinct denticles, at the side of which were several rows of less 

 distinct accessory denticles. No spine or othei- armature was 

 discovered in the reproductive system. 



These specimens seem to clearly belong to Bergh's genus Pteraeo- 

 lidia. There are some small differences (such as the shape of the 

 rhinophores and of the teeth and the lateral ridges) between them 

 and his description and plates of Pteraeolidia (Flabellina) semperi, 

 but the ridges were absent in one specimen and the other characters 

 were slight. It is possible, however, that a compai-ison of the living 

 animals might show a specific difference. 



Ercolania zanzibarica, n. sp. 



(For the genus Ercolania see Trinchese, " Un nuovo genere della 

 fam. degli Eolididei" Ann. del Mus. di Stor. Nat. di Genova, ii. 

 1872; id. " Aeolidjedel Porto di Genova"; Bergh, Beitr. z. Kennt. 

 der Aeolidiaden, v. pp. 9-18, Wien, 1878; Vayssifere, Recherches 

 sur MoU. Opisthobranches, Marseilles, 1888, pp. 121-128.) 



Two specimens captured at Chuaka, East Coast of Zanzibar, 



in February 1901. The living animal was rather more than 



2 centimetres long, veiy fragile and delicate, transparent and of a 



uniform bright green, the hepatic diverticula in the cerata not 



[8] 



