Effects of calcium preloading on the growth of calcium carbonate crystals in the endolymphatic sac of the tree frog, Hyla arborea japonica.

Tree frogs, either with or without calcium chloride preloading, were maintained in a 0.8% strontium chloride solution for 1 week, then studied by X-ray microanalysis and scanning electron microscopy to determine the distribution of incorporated strontium in the endolymphatic crystals. In the absence of calcium preloading, strontium was detected on every surface of all the crystals, but after calcium preloading for 5 or 7 weeks, strontium incorporation was partially or completely inhibited, suggesting that an inhibition of the growth of the endolymphatic crystals had taken place in these preloaded specimens.