20 adult dogs were classified into five groups; in two animals of each group hypoglossal-glossopharyngeal suturing was done. In the other two animals glossopharyngeal nerve transection with concomitant central segment avulsion was done and these two animals were used as controls. The animals of the five groups were sacrificed at 4-week intervals starting by the first group on the 4th post-operative week and ending by the fifth group on the 20th week; the circumvallate papillae were studied. On the 4th week following either operative procedure, few taste buds persisted on the circumvallate papillae. Invasion of the papillae by regenerating hypoglossal fibres from the 8th week onwards was not followed by any appreciable increase in the number of taste buds. The difference in number of taste buds between hypoglossal-glosso-pharyngeal suture and glossopharyngeal avulsion procedures was not statistically significant, from the 8th weeks following cross-innervation the reaction for acetylcholinesterase was more intense than in denervated papillae which showed a persistent weakly positive reaction up to the 20th post-operative week.