24 



of examining a series of specimens belonging to the Eev. J. 

 Crompton, of Norwich, three of them being of considerable 

 interest, as throwing light upon the parasitic nature of the Poly- 

 thoa. One of the specimens was almost entirely divested of the 

 parasite ; but near the top was a small piece of some frondose 

 alga, attached, or rather entangled round the glass rope by several 

 tendril-like filaments, the surface of the fragment being covered 

 with the Polythoa, identically the same as that found investing 

 the ' rope.' The other two specimens are still more remarkable. 

 The Polythoa covers the rope, but beneath it may be seen, in one 

 specimen, a piece of fine twine, and, in the other, a piece of blue 

 paper or cloth. The twine and paper had evidently been wound 

 round the rope in order to keep the filaments together, and the 

 Polythoa (apparently attached to some riband-like alga, about 

 three-quarters of an inch in width) wound round afterwards. 

 This was probably done by some of the Japanese fishermen who 

 dredged up the specimen." 



In the April part of "Annals of Natural History" for 1872 

 Dr. E. Gray writes : — " Mr. Kitten does not seem to be aware 

 that Hyalonema is more common without its parasitical sponge at 

 top than with it ; but the specimens with the sponge were for- 

 merly more sought for by travellers and brought to England, 

 whilst the Russian specimens, being collected by naturalists, 

 were chiefly without this parasite, and now we constantly receive 

 them without any appearance of sponge, covered with living 

 polyps up to the tip." 



In reply to the above remarks by Dr. Q-ray, Mr. Kitten says : 

 — " I am still unconvinced of the parasitic natiire of the sponge, 

 or that the Polythoa is non-parasitic. Until I saw the specimens 

 belonging to the Pev. J. Crompton I was very much inclined to 

 believe that Polythoa was an integral portion of the sponge ; but 

 when I saw it growing on the alga, as stated, and this not 

 entangled on the glass rope (anchoring spicula), but carefully 

 twisted round it, and below it some fine twine, I could only come 

 to the conclusion that the long anchoring spicula did not belong 

 to the Polythoa." 



