272 
currents running past the fenestrae without entering them ; and my 
previous experiments probably failed from the fact of the indigo 
being distasteful to the animal, which exercised its power of not ad- 
mitting it to pass the walls of the sac. 
Another correction which I wish to make is this ; I stated that 
Dr Wright and I thought that, under a high power of the micro- 
scope, we saw a diaphanous membrane stretching across the bran- 
chial stigmata, which showed a polygonal structure similar to that 
of epithelica. I have never been able to detect this again ; but I 
have seen something approaching to it, which I am satisfied was a 
compressed aggregation of blood -globules, and I strongly suspect 
(particularly since finding that the indigo has passed through these 
stigmata) that my former observation is to be referred to some de- 
ceptive appearance of this kind. 
The following Gentleman was elected an Ordinary Fellow — 
Professor Macdougall. 
The following Donations to the Library were announced: — 
On Hypsometrical Measurements by means of the Barometer and 
the Boiling-Point Thermometer. By J. Burgess, F.E.I.S., 
Calcutta, 1859. 8vo. — From the Author. 
Beminiscences of General Sir Thomas Makdougall Brisbane, of 
Brisbane and Makerstoun, Bart. Printed for private circulation. 
4to. 1860. 
Memorial on the new system of Dioptric Lights, invented and in- 
troduced by Sir David Brewster, K.H., to the Lords Com- 
missioners of Her Majesty’s Treasury. 8vo. 1859. — From 
the Author. 
On the Life-Boat, the Lightning-Conductor, and the Light-House. 
By Sir David Brewster, K.H. — From the Author. 
Transactions of the Boyal Scottish Society of Arts. Yol. V., Part 3. 
8 vo. I860.- — From the Society . 
Schriften der Universitat zu Kiel, aus dem Jahre, 1858. 4to.— - 
From the University. 
Charts and Sailing Directions. — From the Depot cle la Marine. 
