on some fossil Bones. 417 
Surface is acted on, and very little when the centre is affected 
by it ; however, this may be accounted for by the parts which 
have lost their phosphoric acid, and acquired the aerial, being 
easiest of solution in the marine add, aqd therefore dissolved 
first, and the aerial acid let loose. 
In some bones of the whale the effervescence is very great ; 
in the Dalmatia and Gibraltar bones it is less; and in those the 
subject of the present paper it is very little, since they contain 
by much the largest proportion of animal substance. 
EXPLANATION OF THE PLATES. 
Tab. XIX. 
Fig. 1. One of the incrusted skulls sent over by the Mar- 
grave of Anspach, which is much larger than that of the com- 
mon white bear, longer for its breadth, and having a greater 
hollow between the anterior part of the skull and the bones 
of the face. 
Fig. 2. Another skull, which differs in many respects from 
fig. 1. and nearly in the same degree that the first does from 
the skull of the recent white bear. 
Tab. XX. 
Fig. 1. A portion of a skull; to what animal it belongs is 
not exactly ascertained, unless it be the growing state of the 
bones in one of the varieties of the white bear species, but it 
is materially different from the full grown skulls expressed in 
Tab. XIX. It is rather too large in proportion to the others. 
Fig. 2. Two of the incrusted ossa humeri, to shew that 
these bones vary very much among themselves, these two be- 
ing in many respects dissimilar. 
3 H 
MDCCXCIVt 
