What’s best description of turtle

From the text:

And over the grass at the roadside a land turtle crawled, turning aside for nothing, dragging his high-domed shell over the grass: His hard legs and yellow-nailed feet threshed slowly through the grass, not really walking, but boosting and dragging his shell along. The barley beards slid off his shell, and the clover burrs fell on him and rolled to the ground. His horny beak was partly open, and his fierce, humorous eyes, under brows like fingernails, stared straight ahead.