e19
e19-
In bell stage ( E19 ), the positive staining was detected in both inner and outer enamel epithelium , but the inner was less than that of the outer and less positive staining was also found in the cells of stratum intermedium and stellate reticulum .
钟状期（胚胎19d），内、外釉上皮阳性表达，但内釉上皮较外釉上皮表达弱，中间层及星网状层细胞弱阳性表达；