8 MARINE BIOLOGY OF THE SUDANESE RED SEA. 
finding of a patch of the branching tubes of a species of Lepralid polyzoan. 
Few Crustacea were found among these, but the number of Polychzeta was 
enormous. The most important is a species of Chetopterus whose tubes 
were enfolded by the polyzoan, and occurred in large numbers. The species 
is probably that which I named C. longipes*, from a single specimen 
obtained by J. Stanley Gardiner in the Maldives. But the great majority 
were small forms, and by placing a tub full of the polyzoan in fresh water 
overnight, I obtained about 4 oz. of representatives of the following families:— 
Terebellidee : 2 species, one of which made up the bulk collected. 
Polynoids: in Jarge numbers. 
Nereids: 2 species. Numerous. 
Hunicidee: a few dozen. 
Syllidee: 2 or 3 species. Fair numbers. 
Sabellidee: 1 species. Fair numbers. 
Serpulidee and Cheetopteridee. Abundant. 
A few each of :— 
Lumbriconereids. 
Hesionids. 
Phyllodocids. 
Besides taking every opportunity of examining buoys and their ropes 
and so on, it is worth while, if one is staying a month in one place, to 
sink half-a-dozen paraffin boxes, or suspend them in the water, and examine 
at the end of one’s stay. In the present case the boxes remained down, 
for a period of five weeks, and at the end of that time presented a wonderful 
appearance, being completely covered with brilliantly coloured compound 
and simple ascidians, some sponges and hydroids and swarms of young 
lamellibranchs. Among these live hosts of free forms. In this way one 
obtains an abundance of specimens of species otherwise rare, or not met with 
at all; in the present case this applied especially to the Planarian worms. 
CoMPARISON OF FAUNA WITH THAT OF THE EQUATORIAL Coast or AFRICA. 
On the whole the two faunas seem much alike, the differences observed 
being perhaps attributable to the differences of habitat and to the ecological 
effects following on the unknown factor which encourages the growth of 
corals here while suppressing them on the Equator. 
Aleyonarians f.—In both localities certain forms, especially the Kentide, 
are in places as abundant as are fucoid weeds on English coasts; but while 
the lowest tides of Zanzibar uncover sheets of blue and blue-greens, the 
shallows of the Red Sea harbours are carpeted with brown. The rapid and_ 
continual motion of some of these brown and grey Xeniids, which 
* P.Z.S. 1904, i. p. 277. 
+ Cf. the account of the East African forms by Prof. J. A. Thomson, P. Z. S. 1906, i. 
pp. 893-443. 
