metapterygium造句

例句與造句

1. Like other members of Stethacanthidae, " Stethacanthus " had unique pelvic girdles, single-crowned and non-growing scales, a pectoral fin composed of metapterygium with an accompanying  whip attached and a distinctive first dorsal fin and spine, termed the Spine-Brush Complex.
2. It's difficult to find metapterygium in a sentence. 用metapterygium造句挺難的