ENDOSKELETON. ANIMALS. 31 



A. 124. A section of the outer compact substance of the palm. 

 0. C. 178. flnntfrian. 



A. 125. A section of part of the os frontis and of the base of a 

 Deer's antler, of which the growth was nearly completed. 

 0. C. 179. 



It shows the antler to be a continuation of bone from the outer 

 table of the skull, and the velvet-like covering of the antler to bo 

 equally continuous with the integuments of the head. It shows 

 also the burr or pearl which has been formed round the base of 

 the antler preparatory to the separation of the vascular integument 

 of the antler from that of the skull. 



In the formation of the burr, which is the last part of the 

 process, and takes place rapidly, the osseous tubercles of which it 

 is composed are projected outwards, and, by their pressure, induce 

 absorption of the vascular external covering at that part. The 

 cessation of the vascular action, or arrest of the unusual deter- 

 mination of blood to the antlers, is due to the same kind of 

 constitutional and seasonal cause or influence as that which excited 

 it : and, as the vessels diminish, the ossification of the burr en- 

 croaches upon their diminishing area ; but it is not the mechanical 

 cause of that diminution. The chief final purpose of the bun- 

 appears to be to defend the margin of the cranial integuments 

 around the base of the antler. When the circulation through the 

 carotids has returned to its normal state, the whole of that once 

 very vascular and sensible tegument loses its vitality, dries, shrinks, 

 and peels off, leaving the antler a naked insensible weapon. 



In one of the branches (the brow antler) in this preparation, 

 the whole of the vessels appear to have been thus obliterated : in 

 the other a slight degree of vascularity remains, and one of the 

 large external arterial branches is still uncompressed. 



Hunterian. 



A. 126. A section of part of the os frontis and base of the antler, 

 which has been completely formed and divested of its 

 external tegument, or ' burnished/ as it is technically 

 termed. This specimen has been injected, and steeped in 

 an acid. 0. C. 180. Hunterian. 



A. 127. A section of part of the os frontis and base of the antler, 

 injected and steeped in an acid, to show the connection of 



