| The cells lining the Wolffian ducts are smaller than those lining the enteron. |
| This structure as has been noted above, is quite distinct from the other parts of the enteron. |
| The mouth opens into the main body cavity, or enteron, which connects with radial canals extending to the outer rim of the bell. |
| Because of the lack of properly fixed tissue no sections of the enteron of this stage were made. |
| The openings of the Wolffian ducts, wdo, are seen at the lower end of the section of the enteron. |
| An outline drawing, from the ventral aspect, of the enteron of an embryo of 20 cm. |
