--"Mr. Robertson, of Brighton, claims the merit of teaching that Pholades perforate rocks by 'the rasping of their valves and the squirting of their syphons.' His observations only appear to reach back to 1851. But the late Mr. John Stark, of Edinburgh, author of the 'Elements of Natural History,' read a paper before the Royal Society of Edinburgh, in 1826, which was printed in the Society's 'Transactions' of that year, in which he demonstrated that the Pholades perforate the shale rocks in which they occur on this coast, by means of the rasping of their valves, and not by acids or other secretions. From also finding that their shells scratched limestone without injury to the fine rasping rugosities, he inferred that it was by the same agency they perforated the hard limestone rocks." To this Mr. Robertson replies, that Mr. Osler also, in 1826, demonstrated that the Pholades "perforate the shale rocks by means of the rasping of their valves; and more, for he actually witnessed a rotatory movement. But Réaumur and Poli had done as much as this in the eighteenth and Sibbald in the seventeenth century: and yet I found the solvent hypothesis in the ascendant among naturalists in 1835, when I first interested myself in the controversy. What I did in 1851 was, I exhibited Pholades at work perforating rocks, and explained how they did it. What I have done is, I have made future controversy impossible, by exhibiting the animals at work, and by discovering the anatomy and the physiology of the perforating instruments. In the words of M. Flourens, 'I made the animals work before my eyes,' and I 'made known their mechanism.' The discovery of the function of the hyaline stylet is not merely a new discovery, it is the discovery of a kind of instrument as yet unique in physiology."