proostracum造句

例句与造句

1. The long, weakly tapering structure in the dorsal anterior part of the internal skeleton is called the proostracum.
2. At the forward part of the phragmocone is a thin very fragile structure known as the " proostracum " ( plural : " proostraca " ).
3. Shortly after this the dorsal median keel first appeared and the inner ( ventral ) apetural lip became retarded while the outer ( dorsal ) lip grows into a gladius-like proostracum ( B . R . & S ).
4. It's difficult to find proostracum in a sentence. 用proostracum造句挺难的