233 



the decay of galena, which he suspects to be itself a secondary pro- 

 duction, arising from the metallization of white carbonate of lead by 

 hepatic gas. This, our author says, appears evident in a specimen 

 which he means to send to Mr. Greville. In one part of this speci- 

 men there is a cluster of large crystals ; one of which, upon being 

 broken, was found to be converted into minium, to a considerable 

 thickness, while its centre was still galena. 



Mr. Smithson does not say where this native minium was found ; 

 but his letter is dated from Cassell in Hesse. 



Description of a rare Species of Worm Shells, discovered at an Island 

 lying off the North-west Coast of the Island of Sumatra, in the East 

 Indies. By J. Griffiths, Esq. Communicated by the Right Hon. Sir 

 Joseph Banks, K.B. P.R.S. Read February 13, 1806. [Phil. 

 Trans. 1806,^. 269.] 



The shells here described were discovered in a small island called 

 Battoo, after a violent earthquake that occurred in the year 1797. 

 Upon the receding of the inundation caused by the earthquake, they 

 were seen protruding from a bank of slightly-indurated mud, in a 

 small sheltered bay, surrounded by coral reefs. They were procured 

 by means of a servant sent by Mr. Griffiths for that purpose, who 

 was very expert in diving, and who stated that he found these shells 

 sticking out of the mud to the extent of ten inches, or even more, 

 and being from one to three fathoms under water. They were in 

 considerable number, standing in different directions, and separate 

 from each other. Mr. Griffiths was informed that the shells were 

 filled with a soft gelatinous flesh, and that the animal threw out 

 tentacula, resembling small Actiniae, from the two apertures at the 

 apex. They were easily extracted from their bed, but were all mu- 

 tilated more or less : this, the author thinks, was occasioned by the 

 earthquake. 



The longest of these shells that came into the possession of Mr. 

 Griffiths was five feet four inches in length. The circumference at 

 the base was nine inches, tapering upwards to two inches and a half. 

 But others were of very different dimensions. The large end of the 

 shell is completely closed, and has a rounded appearance : at this 

 part it is very thin. The small end, or apex, is very brittle, and is 

 divided by a longitudinal septum, which extends downwards eight 

 or ten inches, into two distinct tubes, from whence protrude the 

 tentacula already mentioned. The substance of the shell has a ra- 

 diated appearance, and having an outer crust of a pure white colour, 

 and an inside enamel of a yellow tinge. The external surface is often 

 interrupted by a sudden increase of thickness, which probably indi- 

 cates the different growths of the shells ; but these interruptions are 

 merely on the outside shell, and do not extend into the radiated sub- 

 stance. The thickness of these shells varies very much ; so also does 

 their shape, some being nearly straight, others crooked and con- 

 torted. Their internal surface is generally smooth, but is sometimes 



