R. W. H. ROW—REPORT ON 'THE SPONGES : NON-CALCAREA. 381 
The secondary fibres form a very close but not very regular meshwork, and 
measure 0°02 in diameter. No definite size of the mesh can be given, but 
0-2 mm. is suggested as an approximate average. 
This variety does not seem to be at all definitely distinguished from the 
New-World variety rotunda of the same species. 
Locality. The specimen was obtained on the north-west of Condenser 
Island, Suakin Harbour. 
Distribution of the variety. Red Sea ; Ceylon ; ? Florida. 
THe SPONGE Fauna OF THE Rep Sra. 
The first complete account of the then-known Sponge Fauna of the Red 
Sea was published in 1889 and 1891 by Conrad Keller (18), when he de- 
scribed 88 species of sponges. Since then this list has been increased by 
four other reports on collections, one being by Schulze (27), describing 
3 Hexactinellids, and the other three papers being all by Topsent (31, 32, 35). 
By these four publications the number of known species of sponges was 
increased to 108, and at the time when Mr. Crossland made the collection at 
present being described, this total had not been increased. Of the 93 Species 
of sponges obtained by Mr. Crossland no less than 79 are new to the Red 
Sea, so that there is now a total of 187 species known to occur in this 
region. 
The very large proportion of species new to the Red Sea in Mr. Cross- 
land’s collection is very probably explicable to a very large extent in the 
fact that the area in which he collected was one which had been left almost 
untouched previously. With the exception of the Gulf of Suez, the localities 
which had been investigated when Keller wrote his work on the subject 
were almost entirely confined to the southern portion of the Sea, and the 
most northerly point (save those in the Gulf of Suez) that he obtained 
sponges at was Suakin, almost all his specimens coming from either Suakin, 
Massaua, Asab Bay, or Beilul Bay. The collections investigated by Topsent 
came, one from the Red Sea proper (32), one from the Gulf of Tajoura (31), 
and one from the Gulf of Jibuti (85), both these last two places being just 
outside the Red Sea and in the Gulf of Aden. 
They lie so very close to the Red Sea, however, and the sponge fauna, as 
evidenced by these collections, is so very closely related to that of the Red 
Sea, that I propose to include the Gulf of Aden with the Red Sea in these 
notes as one and the same area. 
At the present time almost the whole of the African coast of the Red Sea 
has been carefully collected over, and the large number of species that have 
been obtained is, J think, evidence that the collecting has been very 
thorough ; but we have practically no knowledge of the fauna of the Asian 
