382 MARINE BIOLOGY OF THE SUDANESE RED SEA. 
side of the Sea, only one spot having been investigated, 7. e. Jeddah, and 
only four species having been obtained there. 
A table is appended (Table A) showing all the localities in the Red Sea 
where sponges have been collected ; and another table (Table B) to show 
the distribution of the various species throughout the globe. 
An examination of this second table will show that the Red Sea shows a 
very considerable affinity to the other parts of the Indian Ocean in its 
sponge fauna. The following 49 species are common to some part of the 
two regions :—Clathring primordialis, Clathrina canariensis var. compacta, 
Clathrina tenuipilosa, Clathrina darwinti, Sycon raphanus, Sycon coronatum, 
Leucandra primigenia, Leucandra microrhaphis, Leucandra pulvinar, Leucilla 
bathybia, Aulocystis zitteli, Tethya lyncurium, Tethya seychellensis, Tethya 
japonica, Tethya ingalli, Suberites carnosus, Terpios viridis, Placospongia melo- 
besioides, Cliona celata, Cliona vastisica, Chondrilla nucula, Chondrosia rent- 
formis, Grayella cyathophora, Tetilla poculifera, Cinachrya schulzer, Reniera 
implexa, Trachyopsis halichondrioides, Ceraochalina pergamentacea, Siphono- 
chalina communis, Siphonochalina tubulosa, Siphonochalina intermedia, Gelli- 
odes poculum, Clathria frondifera, Acanthella awrantiaca, Phakellia donnani, 
Ciocalypta tyleri, Psammopemma commune, Aplysina reticulata, Aplysina 
inflata, Aplysina purpurea, Cacospongia cavernosa, Fircinia variabilis, Hireinia 
fasciculata, Hircinia rugosa, Hireinia clathrata, Phyllospongia radiata, Phyllo- 
spongia otahitica, Phyllospongia madagascariensis, Huspongia officinalis. 
Of these, 17 are common to the Red Sea and the eastern coasts of Africa 
and the islands near, 25 to the Red Sea and Ceylon, and 30 to the Red Sea 
and Australia and the Hast Indies. 
And even such a list of identical species does not exhaust the similarity 
between the two groups. Certain of the genera represented in the Red Sea 
by species confined to that locality, (as far as we know), are represented in 
other parts of the Indian Ocean by very closely allied species, such as 
Paratetilla cineriformis from Ceylon and Paratetilla eccentrica from the Red 
Sea. Paratetilla, moreover, and Aainissa, another genus represented in 
the Red Sea, though not in this collection, are widely distributed over the 
Indian Ocean, but do not occur outside it. 
I therefore propose to enlarge the “ Indo-Australian ” region as defined 
by Ridley and Dendy (24), and enlarged by Dendy (11), to embrace the 
whole of the Indian Ocean, and the whole of the African shores from Suez 
to the Cape of Good Hope ; and I propose to divide it into Hastern and 
Western divisions by a line following the 65th meridian of Hast longitude. 
To justify this division is at present rather difficult, as our knowledge of 
the sponge fauna of the Hast African region is much more scanty than our 
knowledge of the others, and elaborate comparisons of the two faunas are 
therefore impossible. It seems clear, however, from Dendy (41) that the 
I 
