A small stone found in the stomach of some reptiles, fish, and birds that aids in digestion by helping grind ingested food material.
胃石一种小石头，常发现于某些爬虫、鱼和鸟的胃中，通过帮助碾磨食物来帮助消化
This creature can be subsumed in the class of reptiles.
这种生物可以归入爬行动物一类.
reptiles are cold-blooded.
爬行动物是冷血的.
