426 THE DEPTHS OF THE SEA. [CHAP, 1X. 
an additional note on the habitat of THyalonema lusi- 
tanicum. It appears that the fishermen of Setubal 
frequently bring up on their lines, from a consider- 
able depth, coils of silicious threads closely resem- 
bling those of the Japanese species, which they 
even surpass in size, sometimes attaining a length of 
about 50 centimetres. The fishermen seem to be very 
familiar with them. They call them ‘ sea-whips,’ 
but with the characteristic superstition of their class 
they regard all these extraneous matters as ‘ unlucky,’ 
and usually tear them in pieces and throw them 
into the water. Judging from some specimens in 
the British Museum, and from Senhor du Bocage’s 
figure, the ‘ glass-rope’ of the Portuguese form is 
not so thick as that of Hl. sieboldi. There is also 
some slight difference in the sculpture of the long 
needles, but the structure of the sponge and the very 
characteristic forms of the small spicules are identical ‘ 
in the two. I doubt if there be more than varietal 
distinctions between the two forms; and if that be 
so, it adds another to the list of species common to 
our seas and the seas of Japan. 
Perhaps the most singular circumstance connected 
with this discussion was that all this time we had 
been looking at the sponge upside down, and that it 
had never occurred to anyone to reverse it. We had 
probably taken this notion from the specimens stuck 
in stones, brought from Japan, and the sponge cer- 
tainly looked very like the base of the edifice. When- 
ever the sponges were dredged on the coasts of Europe 
and compared with allied things, it became evident 
that the whisp was an organ of support passing out 
of the lower part of the sponge, and that the flat, 
