in the Neighbourhood of Edinburgh. 



219 



Besides the rays which have been assigned to the Gyracanthus, 

 there exists a peculiar kind of Ichthyodorulite, comparatively 

 small, and of an elegant form. But as so much more information 

 is demanded relative to the placoidian animals to which they be- 

 long, any drawings of them may be properly suspended until 

 further remains turn up. 



I have now to state a very important analysis, undertaken by 

 Mr A. Connell, of the bony rays of the Gyracanthus formosus : — 

 Phosphate of Lime with a little Fluoride of Calcium, 53.87 ; 

 Carbonate of Lime 33.86 ; Siliceous matter 10.22 ; Potash and 

 Soda, partly as chlorides, 0.71 ; Bituminous matter 0.54; Phos- 

 phate of Magnesia, a trace ; Animal matter, a trace : Total 99.20. 



NOTES TO SECTION XIV. 



Mr Connell has compared the analysis which he has given of the bony rays of 

 the Gyracanthus formosus with one by M. Dumenil of the bones of the recent pike. 

 I shall throw these two analyses into a tabular form, for the sake of a more ready 

 comparison. 



Analysis of a Thorny Ray of the Gyracanthus 

 formosus, by Arthur Connell, Esq. 



Phosphate of Lime, with a little 



55.26 Fluoride of Calcium, . . 53.87 



Phosphate of Magnesia, . . trace 



Potash and Soda, partly as Chlo- 



1.32 rides, 71 



37.36 Animal Matter, trace 



6.16 Carbonate of Lime, ... 33.86 



Siliceous Matter, 10.22 



Bituminous Matter, ... .54 



Analysis of the Bones of the Pike, by 

 Dumenil. 



Phosphate of Lime, 



Traces of Soda, and loss, 

 Animal Matter, . . . 

 Carbonate of Lime, . . 



100.10 



99.20 



If it be allowable to suppose that there was any original approximation in the qua- 

 lity and quantity of chemical ingredients severally possessed by the bones of the 

 pike and the fossil thorny rays of the Gyracanthus, which is rendered very probable 

 by the proportion of phosphate of lime in each so nearly agreeing, the one analysis 

 yielding 55.26 parts, and the other 53.87 parts in a hundred, — the following obser- 

 vations occur. 



The fossil thorny rays contain a trace only of phosphate of magnesia, which has 

 not been detected in the bones of the pike. 



e e 2 



