1903. ] ON THE MARINE FAUNA OF ZANZIBAR. 169 
2. On the Marine Fauna of Zanzibar and British East Africa, 
from Collections made by Cyril Crossland in the Years 
1901 and 1902.—Polycheta. Part I. By COvynix 
CrossLanp, B.A., B.Sc.1 
[Received January 15, 1903.] 
(Plates XVI. & XVII.) 
Introduction. 
The collections referred to were made under the following 
circumstances :—Sir Charles Eliot, K.C.M.G., C.B., late Fellow 
of All Souls College, Oxford, at present H.M. Consul-General at 
Zanzibar and Commissioner for British East Africa, took me out 
with him as his private assistant in his researches on Nudibranch 
Mollusca. I made collections not only of this, but of the other 
marine groups; accounts of which, by various specialists, will 
appear in these ‘ Proceedings’ from time to time. The largest 
collections are those of the Nudibranchiate Mollusca and Polychete 
Annelids, of which groups about 150 species in each are to be 
described. Sir Charles Eliot has already published one part of the 
results of his examination of the Nudibranchs (P. Z. 8. 1902, vol. ii. 
p- 62); other papers by various authors will shortly be ready. 
For the benefit of other possible workers in this region, I may 
mention that the greater part of my collections was made in two 
localities, viz. Chuaka Bay, on the east coast of Zanzibar, and 
Wasin Harbour, near the Anglo-German boundary on the main- 
land. The former locality is extremely rich in shore forms, and 
dredging in 3 fathoms of water at the north side of the mouth of 
the bay was often very productive. Wasin Harbour averages a 
depth of 10 fathoms, and here I collected almost entirely by 
dredging. The bottom is extensively covered by a species of 
elesto, the branches of which are overgrown by an encrusting red 
sponge. Among this a great variety of the smaller Polycheta 
and Nudibranchiata are found. 
My mention of these two localities is of the more importance to 
future workers because large stretches of the coast are extremely 
barren. Unfortunately this applies to the two principal towns of 
Kast Africa, and especially to Mombasa. A few miles from 
Zanzibar, e.g. round the islands and sandbanks which surround 
the harbour, and on one portion of the shore about a mile to the 
south of the town, at low spring-tide only, ave rich collecting- 
grounds, and near this latter area dredging is profitable, especially 
at a depth of 5 fathoms. The greatest portion of the Zanzibar 
channel is, however, extremely barren. 
More detailed descriptions of the reefs of East Africa, with 
maps, will be found in my two papers: “On the Coral Reefs of 
Zanzibar,” and “ Pemba and British East Africa,” in the Proc. 
Camb. Phil. Soc. vols. xi. & xii. (1902). 
1 Communicated by Pref. W. C. McInrosn, F.Z.S. 
2 For explanation of the Plates, see p. 176. 
