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. 0. 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 Tethyadge. 



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 ffyalonerna-grovLiid 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 

 " sponge-mass is provided with a number of oscula looking upwards, 

 " these being covered over by a beautiful open network of spicules. 

 " When the sponge-mass is washed away or destroyed, the parasitic 

 " Palyihoay 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. 



Mr 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 Loven'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 got Brisinga and the wonderful little 

 Crinoid Rhizocrinus ***** 



Ever truly yours, 



Wtville Thomson. 



