The Regenerative Capacity of the Tail in Embryonic and Post-natal Lizards (lacerta Vivipara Jacquin).

M A N Y studies have been made on autotomy and regeneration of the tail in lizards; for example those by Woodland (1920) and Hughes & New (1959) on geckos, by Slotopolsky (1922) on Lacerta, by Barber (1944) and Kamrin & Singer (1955) on Anolis, and by Simpson (1964) on Lygosoma. This work is concerned with the adult, and, so far as we are aware, no comparable studies on young and embryonic lizards have been made. Indeed, the application of experimental techniques to reptilian embryology is still in its infancy (see Holder & Bellairs, 1962, 1963). In 1956 Panigel found that embryos of the common lizard (Lacerta vivipara) would develop, sometimes until hatching, when removed from the mother and kept under sterile moist conditions in a form of culture. Their yolk is sufficient for nourishment, and the rudimentary type of allanto-placenta which he describes seems to have no significant nutritive function. We have found that embryos of the slow-worm (Anguis fragilis) may also survive for long periods after similar treatment, but a more elaborate form of culture is necessary for their normal development (Raynaud, 1959). Maderson & Bellairs (1962) removed part of the tail in a number of Lacerta embryos kept in Panigel culture, and found, rather surprisingly, that no regeneration took place. This was confirmed by Holder & Bellairs (1962) so that a more thorough investigation of the problem seemed desirable. It was found necessary to re-examine certain general aspects of autotomy and regeneration in lizards in order to assess the results of our experiments.