Fig. 5

Light microscopy micrographs of the foregut of Ceratophrys cranwelli. a and b. Panoramic and detailed sections of the esophagus in advanced larval stage (Stage 39) showing ciliated and goblets cells (PAS-positive) in the lining epithelium. c and d. Panoramic and detail sections of the dilated cranial segment of the gut in an advanced larvae stage (Stage 39) to display the fundic region with numerous gastric glands and some goblet cells (PAS-positive). e. Sections of the transitional zone between the esophageal-like region and the fundic region with some gastric glands in a specimen at the end of metamorphosis (Stage 46). f. Section of the middle stomach showing a folded mucosa and numerous gastric glands in a specimen at the end of metamorphosis (Stage 46). The mucous glands are PAS-positive. g. A section at the level of the pyloric region with few PAS-positive goblets cells in advanced larval stage (Stage 39). h. Section at the level of the pyloric region has some small simple tubular gastric glands in a specimen at the end of the metamorphosis (Stage 46). Abbreviations: Ec: epithelial cells; Gc: goblets cell; Gg: gastric glands; Gp: gastric pits; Me: muscularis externa; Mm: muscularis mucosa; Mnc: mucous neck cells; Sm: submucosa