Dr Traquair on the StrucUcre, of Pycnodont Fishes. 263 



look for the explanation of these in the meeting of the silica 

 present in the vegetable matter heaped on the wall in order 

 to calcination, with the potash or the soda in the stones ? 



The specimens illustrative of prismatic structure now shown 

 to the Society are from Finhaven, Forfar ; Knockfarrel, Koss ; 

 Dun Mac Nisneaclian, Argyle; and Craig Phadrick, Inverness. 



VI. Oil the Structure of Pycnodont Fishes. By Dr E. H. 

 Traquair. 



In this paper the author gave an account of the peculiar 

 family of ganoid fishes known as Pycnodo7itidce, and also 

 took occasion to compare their structure in many points with 

 that of the Platysomidm. The latter family, the author 

 maintained, are not related to the Pycnodonts, but are, on the 

 other hand, closely allied to the Palceoniscidm. 



Wednesday, 17th April 1878.— Dr R. H. Traquair, F.G.S,, President, 

 in the Chair. 



The following gentlemen were balloted for, and duly elected Resident 

 Members : 



"William Hamilton Beattie, Esq., Architect, 68 George Street; Alexander 

 Thomson, Esq., Newbank, Trinity; Francis A. Bringloe, Esq., 75 George 

 Street; John Cameron, Esq., S.S.C., 63 George Street; Hvpolite W. Cor- 

 nillon, Esq., S.S.C., 67 George Street ; George W. Watson, Esq., 4 Stafford 

 Street; John Maclauchlan, Esq., Principal Librarian, Free Librarj^, Dundee. 



The following donations to the Library were laid on the table, and thanks 

 voted to the donors : 



1, Proceedings of thePoyal Society [London], Vol. XXVIL, No. 185.— From 



the Society. 2. Journal of the Linnean Society — Zoologj^ Vol. XIII., No. 72 ; 

 Botany, Vol. XVI., JSTo. 95. — From the Society. 3. Proceedings of the Literary 

 and Philosophical Society of Liverpool, for 1876-77. — From the Society. 4. 

 Transactions of the Geological Society of Glasgow, Vol. V., Part 2. — From the 

 Society. 5. Annual Report of the Geologists' Association [London], for 

 1877. — From the Association. 6. Annual Address to the Chicago Academy 

 of Sciences by the President [E. W. Blatchford], 1878. — From the Academy. 

 7. Boletin del Ministerio de Fomento de la Kepublica Mexicana. Seccion 

 Astronomica, Tomo I., ISTum, 87, 88; Tomo II., Num. 1 -27. — From the Central 

 Meteorological Observatorv, Mexico. 8. Medical Examiner, Vol. III., Nos. 

 112-118.— From the Publishers. 



The following communications were read : 



