Enamel prism patterns and enamel deposition rates were compared for specimens representing six mammalian orders. Enamel samples were characterized by either pattern 1 or pattern 3 prisms. Each prism pattern cate-gory contained prisms from at least two mammalian orders. Enamel deposition rate was estimated for each sample by measuring prism cross striation repeat intervals. Statistical analysis of cross striation repeat intervals illustrates significant differences in deposition rate between prism patterns 1 and 3. No statistically significant differences were found in deposition rate between the higher-level taxa represented within each prism pat-tern category. That enamel deposition rate is not taxon-specific reinforces the close association between deposition rate and prism morphology. In accord with previous studies, pattern 1 enamel is deposited more slowly than is pattern 3 enamel. Correlation analyses illustrated a lack of association between enamel deposition rate and body mass, tooth size, and estimated ameloblast size. Evidence that enamel deposition rate is associated with enamel prism morphology, coupled with evidence that deposition rate is not correlated with size parameters, points to developmental homology (i.e., homogeneous deposition rate) within each prism pattern
