352 



Miscellaneous, 



a longer time to grind down the irregularities of the surface, which 

 is best effected by rubbing them upon a piece of wet unpolished 

 marble. 



For the deeper cells Mr. Thwaites finds nothing so good as marine 

 glue, which must be melted and dropped on the slip of glass, like 

 sealing-wax, then warmed and flattened with a piece of wet glass : 

 what is superfluous must be cut away with a knife, so as to leave 

 only the wall of the cell ; should this become loose, it ean easily be 

 fixed by heating the other side of the slip of glass over a spirit-lamp 

 and gently pressing. Before these cells are used, it is desirable to 

 flatten them by rubbing gently upon a piece of wood and then upon 

 the wet marble. 



In using the cells, as small a quantity as possible of gold- size, 

 of a thick consistence, should be laid on the wall of the cell, and also 

 on the edge of the piece of thin glass ; and in covering up the cells, 

 gentle pressure should be employed in order to squeeze out the su- 

 perfluous fluid. 



It would be a very useful thing for travellers to take with them 

 the proper ingredients for preparing the two solutions for fresh and 

 marine algae. A portion of each species of alga might then be pre- 

 served in small phials carefully sealed and ticketed, which may be 

 mounted and observed at leisure. The benefit of such a practice has 

 been strongly impressed upon me during the examination of some 

 highly curious foreign algae which have lost many of their distinctive 

 characters in drying. M. J. Berkeley. 



On the Discovery of a Fossil Frog and Butterfiy in the Gypsum Deposits 

 of Aix. By M. Coquand. 



Among the fossils in my possession from the gypsum formation of 

 Aix, a remarkable and very distinct impression of a reptile belonging 

 to the order of the Batracians, and to the family Anoura, has par- 

 ticularly caught my attention : M. Boue (Guide du Geol. vol. ii. 

 p. 259) notices indeed, in the tertiary formations, the presence of 

 some reptiles, such as salamanders, frogs and ophidians ; but as 

 he does not enter into any details, either of their description or the 

 localities in which they have been found, the palaeontologist will 

 perhaps read with interest some details respecting the species in my 

 possession. Its dimensions are as follows : — 



Millimetres 



Total length of the body, inclu- 

 ding the head 32 



Great diameter of the head ... 13 



Transversal diameter 8 



Diameter of the sternum at the 



origin of the anterior feet ... 9 



Length of the humerus 6 



The body of this species, which I shall name Rana aquensis, is not 

 so plump as that of the common frog ; its head, although as flat, is 

 more elongated, and is terminated by a snout which describes an al- 



Millimetres 



Cubitus and radius 



truncated in part 



Femur 12 



Tibia 12 



Tarsus 7 



Toe of the posterior foot 5 



