Zoological Proceedings of Societies. 581 



it has been assumed that they furnished nutriment to the Oyster 

 which, while feeding on this apparently vegetable matter, acquired 

 the green colour that is occasionally remarked in those that are 

 supplied from the reservoirs in which they are preserved to fatten. 

 This opinion is controverted by M. Gaillon, whose observations 

 tend to show that in their aggregated state these animalcula are 

 incapable of being taken in by the nutritive organs of the oyster, 

 which are only adapted to imbibe them in their separate form. In 

 this state they furnish the most advantageous nutriment; the 

 oyster becoming fat and tender, and acquiring a peculiarly agree- 

 able flavour. This portion of the enquiry may however seem 

 fitted rather for the pages of the Almanach des Gourmands 

 than for ours, and we shall therefore merely mention that, in addi- 

 tion to the green Navicula (Vibrio navicularis Auct.) which 

 furnishes this excellent food, various species of this and other 

 genera of Infusoria are referred to as beneficial to the oyster, 

 while some are described as injurious to it. The paper is indeed 

 full of curious matter, and is well deserving of attention. 



The last article to which it is necessary to refer is one by 

 M. de Basoches on a Fossil Shell, which he names Melania La- 

 fresnayi. It is of considerable size, and approaches more nearly 

 to the M. striata of Sowerby's Mineral Conchology, than to any 

 other published species. Casts of it are not uncommon at Fresnay, 

 but only a single mutilated specimen of the shell, of which a figure 

 is given, has yet been discovered. 



AiiT. LXX. Proceedings of Learned Societies on subjects 

 connected with Zoologi/. 



ROYAL SOCIETY. 



The meetings of this learned body were resumed on the 18th 

 of November 1824; when the following papers were read: 



The Croonian Lecture ; by Sir E. Home, Bart. M. D. V.P.R.S. 

 In this Lecture Sir Everard announced his discovery of nerves on 

 the ftctal and maternal surfaces of the placenta. 



