Roundsided

Protoconch proportionally large, consisting of about 4" smooth whorls that become increasingly roundsided with increased size.

Source: wiktionary

Only one form is represented in the sample, a roundsided bowl with slightly restricted orifice and flat base and an estimated rim diameter of 17 cm.

Source: wiktionary

I'm riddled at the hips and knees, roundsided as parentheses since my shrunken spine has known osteoporosis and my extremities have shriveled into lacy filigrees, breakable as glass on stone.

Source: wiktionary