A. d'A. Bellairs

Effects of amputation of limbs and digits of lacertid lizards

Although the majority of adult lizards are able to regenerate lost portions of tails, only rarely have instances of limb or digit regeneration been observed. The present work describes the histological features of the stumps of limbs and digits of Lacerta vivipara and Lacerta dugesii at various times after amputation, and compares these features with those which are seen after amputation or autotomy of the tail. The results show that the early stages of healing of the limbs and digits are similar to the early stages of tail regeneration. The epidermis which migrates over the wound becomes thickened, and cells released from dedifferentiating stump tissues accumulate beneath it. In one case, that of a digit, a papilla was seen extending from the wound epidermis into the blastema. During the later stages of healing differences between the events taking place in the limbs and digits, and the tail, become marked. The blastema fails to increase in size, and it appears that most of its cells are converted into a cartilage cap and sleeve investing the cut end of the bone. An investigation has also been made of the regenerative ability of the limbs of embryonic Lacerta vivipara. Limbs were amputated in ovo at various stages of embryonic life, but no cases of regeneration were observed.