320 Miscellaneous. 
like down; the peduncle is formed of spirally twisted threads, and 
divides below into a few rootlets: ” and he believes that the sponge 
grows sticking in the mud. 
Dr. O. Schmidt kindly sent me a slide with specimens of the spi- 
cules of Tetilla, but I do not find any trifurcated spicules on it ; one 
of them is figured across the base of the sponge, t. 5. f.10. It also 
belongs to Tethyade. 
On Hyalonema, Gray. 
Professor E. Perceval Wright of Dublin has just returned from 
Setuval, where, with the kind assistance of Prof. Bocage of Lisbon, 
he has succeeded in dredging living specimens of this strange 
organism. The Hyalonema-ground is in a valley, some thirty miles 
to sea, south-west of Setuval, and is from 400 to 500 fathoms in 
depth. Prof. Wright “‘ regards the siliceous axis as the stem of the 
*‘ sponge-mass called Carteria by Dr. J. E. Gray, and has deter- 
“‘ mined that the end of the axis, where the fibres become loose, is 
‘that one imbedded in the mud, the sponge-mass being on the 
“summit, and presenting forms of very various outline. The 
“‘ snponge-mass is provided witha number of oscula looking upwards, 
“these being covered over by a beavtiful open network of spicules. 
«‘ When the sponge-mass is washed away or destroyed, the parasitic 
“« Palythoa, which was seen living, and in the act of protruding its 
“tentacles, grows up over that portion of the siliceous axis which is 
“left uncovered by the mud; but numerous examples of the sili- 
“‘ceous stem exist uncovered by the parasite. The Lisbon Museum 
“has now, thanks to Prof. Bocage, the most magnificent series of 
“this sponge in the world.’ Prof. Wright will shortly publish 
fuller details of this interesting discovery. 
Castle, Dublin, Sept. 22nd. 
My Dear Dr. Gray,—Many thanks for your kind note, which I 
got on my return from the expedition Carpenter and I made to the 
North Sea:* * = = —* 
Now, as to our expedition. In the mud of the Gulf Stream (at 
550 fathoms) we got Hyalonema living upside down, as I already 
suspected from Lovén’s paper; but, besides Hyalonema, we got at 
least half a dozen new forms of vitreous sponges, most remarkable, 
and some of them as beautiful as the flower-basket. 
Of these you will, of course, get specimens; but in the first place 
I must clean and prepare them and describe them for the ‘ Phil. 
Trans.’ 
In another locality we Bl Brisinga and the wonderful little 
Crinoid Rhizocrinus * * * * 
Eyer truly yours, 
Wryvitie THomson. 
