38 Proceedings of the Royal Physical Society. 
Presidents. — Andrew Murray, Esq., W.S. ; William Rhind, Esq. ; 
Thomas Strethill Wright, M.D. 
Council. — W. H. Lowe, M.D. ; Alexander Rose, Esq. ; George Logan, 
Esq., W.S. ; John Hutton Balfour, M.D., Professor of Botany, Univer- 
sity ; James M'Bain, M.D., R.N. ; John Coldstream, M.D. 
Secretary. — John Alexander Smith, M.D. 
Assistant Secretary. — James Boyd Davies, Esq. 
Treasurer. — William Oliphant, Esq. 
Honorary Librarian. — Robert F. Logan, Esq. 
Library Committee. — John L. Stewart, Esq. ; Alexander Bryson, Esq. ; 
Patrick Dalmahoy, Esq., W.S. 
The following Donations to the Library were laid on the table, and 
thanks voted to the donors : — 
1. Annales des Sciences Physiques et Naturelles d' Agriculture et d'ln- 
dustrie, Publiees par la Societe Royal d' Agriculture, <S:c., de Lyon, 
Tomes VL, VIL, VIIL, IX., X., and XI.— From the Royal Society of 
Agriculture and Industry of Lyons. 2. Geological Survey of Canada — 
Report of Progress for the years 1853-56, printed by order of the Legis- 
lative Assembly, Toronto ; with quarto Atlas of various lakes and rivers. 
' — From Sir W. E. Logan. 
The following communications were then read : — 
I. Mr Rhind exhibited a specimen of black shale, displaying a branch 
of Lepidodendron several inches in length, with the Lepidostrobus at- 
tached to its extremity, which was found by Mr R. H. Traquair, in the 
beginning of August last, in a stratum of very fissile black shale exposed 
in the bed of the Water of Leith, a little below the church at Colinton, 
This shale abounds in the stems of Lepidodendra., in detached Lejndo- 
strobi and Lepidophylli ; and in what seems to be impressions of very 
delicate bivalve shells ; also in Cy prides, ' and detached scales of the 
Palceoniscus . Notwithstanding the abundance of the two first-mentioned 
fossils {Lepidodendron and Lepidostrobus).^ this specimen is the only one 
Mr Traquair had ever found exhibiting them in distinct apposition. 
II. On the Cnidae or Thread-cells of the Eolidse. By T. Stbethill 
Wright, M.D. 
Dr Wright, after describing the anatomy of the respiratory, digestive, 
and hepatic organs in the Eolidae, stated that, in his Memoir on Hydrac- 
tinia echinata, read before the Society, November 26, 1856, he had ob- 
served, " Hydractinia is infested by a small species of Eolis {Eolis nana), 
which peels oiF the polypary with its rasp-like tongue, and devours it, — 
possessed, I suppose, of some potent magic, which renders all the formid- 
able armament of its prey of no avail. Now, each of the dorsal papillae 
