Distribution of taste buds on the lips and inside the mouth in a minnow, Pseudorasbora parva.

The distribution and abundance of taste buds were quantitatively examined by observing silver impregnated serial sections. The taste buds were widely dispersed on the skin, the lips, the mucosa in the oro-pharyngeal cavity, the esophagus, and the branchial apparatus. The great majority of them was found on the lips and inside the mouth. The external buds were concentrated especially on the outer lips and the adjacent skin, while their number diminished in a caudal direction. Very few were found on the scaled skin. The total number of external buds in a specimen of 6 cm in length was 1,486. The number of taste buds inside the mouth was 6,600. On the inner lips and the palatal organ densities were found to reach over 140 per mm2. High concentrations of taste buds were also found on the gill arches and rakers. These taste buds varied to some extent in size and shape, depending on the thickness of the epithelial layer. It is suggested that the minnow may use the lips, gills and palatal organ as its main taste organs.