HISTORY OF THE SOCIETY. 



467 



culiar growth of the Senecio Jacobsea, by J. W. Reddoch, 

 Esq. Falkirk Professor Jameson then communicated an analy- 

 sis, by Mr Walker, of the substance of the fossil tree lately 

 found in the strata of Craigleith Quarry ; shewing that, besides 

 lime and alumina, and a comparatively small amount of silica, it 

 contains a considerable proportion of carbonate of magnesia, the 

 last being an ingredient not detected in the fossil trunks previ- 

 ously discovered in the quarry Dr Traill exhibited one of his 



portfolios, containing the figures of some new birds, fishes, &c., 

 and gave some account of them. 



Professor Jameson, President, in the chair. — Dr Traill read p^^\ 

 a memoir of the Rev. George Low, the naturalist of Orkney, 

 and laid before the meeting some of his unpublislied sketches 

 and original notes. — Dr Stark, in the absence of his father, read 

 a notice regarding the Mytilus polymorphus of Pallas, a colony 

 of which was lately detected in the Union Canal not far from 

 Edinburgh. — Dr Allen Thomson then communicated remarks on 

 foetal development in its early stages, and exhibited several spe- 

 cimens of the foetus of the domestic cat between the thirteenth 

 and fifteenth day ; also of the foetus of the common fowl and 

 swan, and of a double monstrous foetus of the goose. 



Professor Jameson, President, in the chair — Dr Thomas J. Feb. 15. 

 Aitkin read a memoir on the nerves of smell and hearing in the 

 cod, and illustrated his observations by a demonstration of the 

 nerves, especially the olfactory, in the head of a large specimen 

 of the fish. — Dr John Coldstream then read a paper on the struc- 

 ture and habits of the Limnoria terebrans, a small crustaceous 

 animal which destroys wooden erections on our shores ; and ex- 

 hibited sketches of the animal, and specimens of the timber 

 which had suffered from its depredations. 



Dr Robert Kaye Greville, Vice-President, in the chair Pro- March 1. 



Gg2 



