372 Proceedings of the 



formed of only a very small number. In the animals of the 

 second colony — under a power of 800 diameters — each rod 

 assumed a beaded structure (fig. 2), which I had not before 

 observed. 



The animal secretes beneath itself, or from its base, a 

 pedicle of diaphanous and colourless substance, which in- 

 creases in length and breadth with the increasing growth of 

 the animal, until it assumes the form of a long glassy club, 

 on the thick upper extremity of which the animal is seated. 

 The whole of the pedicle is covered by a growth of scattered 

 hairs, but it may be doubted whether these have any organic 

 connection with it, and whether they do not belong to one of 

 those minute classes of Algae, the structure of which eludes 

 microscopic research. A longitudinal fibrous structure is 

 faintly seen in the axis of the pedicle, but it gradually disap- 

 pears towards the periphery. After immersion in spirit, this 

 fibrous structure becomes much more apparent. The action of 

 the spirit, also, causes a fine membrane to separate from the 

 surface of the pedicle, which appears to be continued down- 

 wards from the body of the animal, and is probably analo- 

 gous to the membrane which I have already shown to exist as 

 a lining and covering to the cell of Vagincola valvata, and 

 which secretes and hides within itself the valve that closes the 

 cell of that curious animal. 



Dr Weight also exhibited living specimens of the new Laomedea 

 acuminata (Alder), with its medusoids. 



Several specimens of the Clouded Saffron Butterfly, Colias edusa (in- 

 cluding two females), taken in the county of Dumfries, were exhibited by 

 Mr W. Stewart Thorburn ; a visitor for the evening. This insect has 

 hitherto been very rarely met with in Scotland. 



, 23d December 1857- — Professor Balfour, President, in 

 the Chair. 



The following gentlemen were elected the Office-Bearers for the Session 



1857-3: — 



Presidents. — J. H. Balfour, M.D., Professor of Botany, University of 

 Edinburgh ; Andrew Murray, Esq., W.S. ; William Rhind, Esq. 



Council. — M. Forster Heddle, M.D.; Robert Chambers, Esq.; Thomas 



