Intelligence and Miscellaneous Articles. 331 



very hard, and to give it much of the appearance of a mass of arra- 

 gonite, of which it has also the form. Its stem is irregularly cylin- 

 drical, rather crooked, and slightly tapering : it throws off a rather 

 thinner branch a little below the middle of the main stem ; and both 

 the main stem and its branch end in a hemispherical head, the upper 

 surface of which is covered with forty or fifty rather large conical 

 tubercles, each terminating in a small central mouth. These tuber- 

 cles are formed of spicula resembling those of the stem, the points 

 of which arm the apices of the cones. The central cones are the 

 largest and most distinct, and the marginal ones are smaller, and 

 more or less confluent. The stem when broken exhibits similar spi- 

 cula and a few internal cells, but it has no distinct central axis : the 

 conical tubercles of the head are hollow, and they doubtless inclose 

 and give exit through their central mouths to the Polypes which form 

 the coral. 



This coral appears to be most nearly allied to the genus Zenia (of 

 which Alcyonium fioridum. of Esper is the type), and agrees with it 

 in having no distinct axis, and in having the whole surface covered 

 with large spicula, arid the Polypes protruded from tubular cells at 

 the end of the branches. It differs, however, from that genus in 

 its spicula being much more abundant, and the coral consequently 

 more solid, and by no means spongy ; and in being less branched, 

 with the polype-cells forming a hemispherical head, instead of a 

 bunch of small branches. For these reasons Mr. Gray is led to con- 

 sider it as forming a new genus, which, until the animal is known, he 

 is induced to place next to Zenia, with the following characters : 



Genus Nidalia. 



Corallium fixum, cylindricum, subramosum, subsolidum, spiculis 

 calcareis dense indutum ; apice capitato, hemisphaerico, e pa- 

 pillis conicis insequalibus spiculiferis formato. 

 Nidalia Occidentalis. Nid. corallio albido, subramoso. 

 Hab. in littore Oceani Atlantici apud Montserrat in India Occi- 

 dentali. 



The specimen described is now in the collection of the British 

 Museum. 



XXXVI. Intelligence and Miscellaneous Articles. 



ON THE EXISTENCE OF ARSENIC IN PHOSPHORUS. 



MHERTN, a druggist of Berlin, found that some phosphoric acid, 

 • prepared according to the Berlin Pharmacopoeia, by treating 

 phosphorus with nitric acid, became of a yellow colour after some time, 

 on the addition of sulphuretted hydrogen. M. Barwald passed a cur- 

 rent of sulphuretted hydrogen through phosphoric acid, prepared by 

 the method above mentioned : from a pound of acid he obtained eight 

 grains of a precipitate, which being mixed with carbonate of soda was 

 decomposed in a glass tube by dry hydrogen. In the upper part of 

 the tube a metallic layer was deposited, which from its appearance, 

 and also from the odour of garlic which it emitted when thrown on sea 



2U2 



