256 SIR CHARLES ELIOT ON NUDIBRANCHS [Mar. 17, 
vivid crimson-lake, The body of the rhinophores is brown and 
inconspicuous, but the tips are whitish and have a crimson ring. 
Although the colour of the animal when analysed is as described, 
the general effect in most lights is that it is purple with a silvery 
glaze. 
The specimens were active in their movements, and in particular 
the long oral tentacles were very mobile. The anterior margin of 
the foot was produced into two deeply-grooved processes, and its 
sides projected in two laminz 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 were from 10 to 20 cerata. The largest individual 
appeared to have about 640 cerata in all. None of the cerata 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 preserved specimens there was a very 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 remarkable character was not visible. The oral tentacles were 
very large and long; the rhinophores, which stand between the 
first clumps of cerata, were small and lamellated, except the tips, 
which were narrow 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 (J. c. 
pl. i. 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 other 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 (Hlabellina) sempert, 
but the ridges were absent in one specimen and the other characters 
were slight. It is possible, however, that a comparison of the living 
animals might show a specific difference. 
ERCOLANIA ZANZIBARICA, 0. Sp. 
(For the genus Hrcolania see Trinchese, ‘Un nuovo genere della 
fam. degli Holididei,” Ann. del Mus. di Stor. Nat. di Genova, ii. 
1872; id. ‘“‘ Aeolidee del Porto di Genova”; Bergh, Beitr. z. Kennt. 
der Acolidiaden, v. pp. 9-18, Wien, 1878; Vayssiére, Recherches 
sur Moll. 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, very fragile and delicate, transparent and of a 
uniform bright green, the hepatic diverticula in the cerata not 
