1903. ] FROM EAST AFRICA AND ZANZIBAR. 255 
The jaws were large, with a smooth cutting-edge. The radula 
consisted of a single series of 13 transparent yellowish teeth of the 
shape usual in the genus, viz., pectiniform, with large irregular 
denticles and small accessory denticles. It was sometimes hard 
to decide whether the rather small denticles should be considered 
main or accessory; but the average number of main denticles on 
each tooth was 10, and the largest number (in one case only) 13. 
The central nervous system was somewhat concentrated. The 
specimen was only partly dissected. 
A new species must, I think, be provisionally created for this 
animal, though the discovery of intermediate forms may perhaps 
render its retention unnecessary. In some ways it is itself a con- 
necting-link between C. longicirrha and C. annulata, for the former 
is said to have 7, and the latter 5 denticles on each side of its 
teeth, whereas C. africana has 4, 5, 6, ov 7 indifferently. It can 
hardly be C. annulata, for the difference in colour is too great, 
and besides there is much less bare space on the back. Neither 
can it be C. longicirrha, because (1) the coloration, though similar, 
is still distinct ; (2) C. longictrrha has the back bare up to the 7th 
row of cerata, and some of the cerata are very long, which is not 
the case here; (3) the rhinophores are not perfoliate. 
This last pomt is of some importance for the characterisation 
of the genus. In the present animal the rhinophores were 
undoubtedly quite simple in life, and in alcohol they are wrinkled, 
though it is still possible to see that they are not really perfoliate. 
In C. longicirrha, Bergh says the perfoliations are 14 or 15 in 
number, and not deep. Of C. annulata he says that the rhino- 
phores have 12-14 well-marked perfoliations, and that Garrett has 
wrongly represented them as simple. But im Semper’s ‘ Reisen,’ 
xvii. he states that C. annulata var. affinis has simple rhinophores, 
and gives as a generic character: ‘‘ Die Rhinophorien scheinen 
nicht perfoliirt zu sein.” I have not access to part 1x. of his 
‘ Beitriige zur _Kenntniss der Aeolidiaden,’ which perhaps explains 
the matter; but it looks as if the rhinophor es are simple, but have 
a tendency to simulate perfoliations when preserved. 
PYrERAEOLIDIA SEMPERI. 
(Bergh, Beitr. zw Kennt. der Aeolidiaden, iii. p. 22, and in 
Semper’s Reisen, Malac. Untersuch. vol. i. p. 18 (1870); under 
Flabellina.) 
Four specimens, which seem probably referable to this species, 
were dredged from 3 fathoms near Chuaka in July 1901. The body 
is very long, narrow, and vermiform, the largest individual being 
5°5 centim,. long and only 3 millim. broad. The ground-colour of 
the body in the living animal is brown, with opaque markings of 
very light green on the sides and back. The cerata are also dark 
brown, with numerous thin lines of the same green. The top of 
the head and the ends of the oral tentacles are opaque yellowish 
white. The lower part of the tentacles brown, with three rings of 
Proc. Zoot. Soc.—1903, Vout. I. No. XVII. Ai 
