Investigations were conducted on 93 tongues of the rabbit, which were col-lected at day 15, 18, 20, 22 and 26 of prenatal life (p.c.) and at day 1, 15 and 30 and at month 6 of postnatal life (p.p.). The height of epithelial thickenings being the first forms of primordia of vallate papillae increased in the period from day 15 to 20 p.c. and the differences between mean values of the analyzed trait were statistically highly significant, p ≤ 0.01. Between day 22 p.c. and the 6th month p.p. developing vallate papillae, having in their structure a connective tissue core, increased in height. Differences in mean values of the analyzed trait between individual periods of life in the rabbit were statistically highly significant, p ≤ 0.01. Morphometric analyses showed that starting from day 22 p.c. up to the 6th month p.p. the thickness of epithelium also increased. Between day 22 and 26 p.c. and between day 26 p.c. and day 1 p.p. no statistical differences were observed, p > 0.05. Between day 15 and 30 p.p. statistical differences were recorded, p ≤ 0.05. In the other analyzed periods differences between means for the analyzed trait were statistically highly significant, p ≤ 0.01. Analyses showed that the growth rate for the thickness of the epithelium in successive analyzed periods in the life of the rabbit was more uniform than the growth rate for the height of developing vallate papillae.

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