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The Hyalonema has long been a favourite with collectors from the intrinsic beauty of its form, whilst to the student of marine zoology it has a special interest from the peculiarities of its structure, the doubt that obtained as to the precise position it occupied in the animal kingdom, and from an uncertainty, not even yet definitely set at rest, as to the true relation which the parts of which it is composed, namely, the sponge head, the glass rope, and the so-called bark or polythoa, bear one to another.
Dr. Gray, who described the Hyalonema from some of the early specimens and gave it its scientific name, regarded the glass rope and its bark-like enveloping polythoa as an organism entirely independent of the spongy mass to which it was commonly found attached, and the glass rope with its coriaceous investment were described together as barked coral, the silicious twisted stem or axis being looked upon as the foot selection or sclero basic corallum, as it is termed, of the compound polyp mass investing it and forming its bark. Dr. Gray considered its attachment to the sponge as merely parasitic and accidental, the sponge being supposed to form a fixed base from which the Hyalonema grew and projected like a plume. In a very trustworthy little work by Professor Reay Greene published in 1863, the Hyalonemas are referred to the Actinozoa, although provisionally, and since that time our knowledge of them has increased. In 1868 it was reported that Hyalonemas had been discovered in the deep sea dredgings at Setubal on the coast of Portugal. It was first supposed that these must have been thrown overboard from some passing vessel returning from Japan, but other fresh specimens followed and it became certain that the Hyalonema was a denizen of Portuguese waters. Since that time the deep sea dredgings of Setubal, carried on at depths of 300 and 400 fathoms, have been a kind of happy hunting-ground for marine zoologists. A fine collection has been secured for Lisbon. Professor Percival Wright was successful in finding specimens, some living, and some of large size, and has shown us that our original opinions were founded in
