247 
of Edinburgh, Session 1873-74. 
The superior temporo-sphenoidal gyrus, though for the most 
part situated under cover of the squamous-temporal and great 
wing of the sphenoid, yet ascends into both the lower antero- and 
lower postero-parietal areas. 
The area covered by the parietal bone, so far then from being 
conterminous with the parietal lobe of the cerebrum, is trenched 
on anteriorly, posteriorly and inferiorly by three of the other lobes 
of the brain. The convolutions of the parietal lobe itself are 
especially grouped round the parietal eminence, and in the interval 
between that structure and the sagittal suture. 
The Insula or central lobe does not come to the surface, but 
lies deep in the Sylvian fissure, and is concealed by the convolu- 
tions which form the margin of that fissure anteriorly. It lies 
opposite the upper part of the great wing of the sphenoid and its 
line of articulation with the antero-inferior angle of the parietal 
and the squamous part of the temporal. 
3. On some Peculiarities in the Embryogeny of Tropceolum 
speciosum, Endl. & Poepp., and T. peregrinum , L. By 
Professor Alexander Dickson. 
4. Notes on Mr Sang’s Communication of 7th April 1873 
on a Singular Property possessed by the Fluid enclosed in 
Crystal Cavities in Iceland Spar. (1.) By Professor Tait ; 
(2.) By Professor Swan. 
(1.) Professor Tait. 
The very beautiful experiment of Mr Sang, communicated to 
the Society on the 7th April, 1873, suggested to me, as soon as I 
heard him read his description of it, an explanation which was 
confirmed by a subsequent examination of his specimens. Some 
remarks made to me by members of the Council of the Society, 
three days afterwards, led me to write, and deposit (under seal, 
as Mr Sang had announced that he was still prosecuting his 
inquiry) with the Secretary the following hastily written docu- 
2 i 
VOL. VIII. 
