1905. | REGENERATION OF THE TAILS OF MICE. 493 
similar to that in Lizards, there being a central tube filled with 
soft or cartilaginous matter, and surrounded by a cylindrical bony 
envelope, of similar appearance and texture to the true caudal 
vertebrae. A proper microscopic examination and report would, 
it was hoped, be made by Dr. Ridewood. 
In the third specimen from the French Congo the tail had 
been broken at about a third of its length, and the regenerated 
terminal vertebra, with its spike, measured 15 mm. in length. 
Text-fig. 70.—Tail-vertebre and regenerated appendix of a species of 
Central Asian Hliomys. 
Text-fig. 71.—Tail of a species of Graphiwrus from Fernando Po showing 
regenerated appendix. ; 
It seemed clear from these specimens, from the type of Claviglis 
crassicaudatus, as described by Dr. Jentink, and from the ap- 
pearance presented by certain other skins of Graphiurus in the 
Museum Collection, that in the not uncommon event of losing 
part of their tail, Dormice—perhaps of all species—were able to 
supply the place of the lost part by swelling up what remained 
into a club-shaped organ, clothed externally with abnormally 
long hairs, and supported internally by an elongated rod of bone 
growing out of the vertebra in which the break had occurred. 
Such a regeneration would be of essential value to the animal, 
for, in climbing, the tail was used as a balancer, and, if broken off 
