| absent | |
| present |
| with diverticulum | |
| without diverticulum |
| absent | |
| present |
| bursal canal absent | |
| curves distinctly anteriad | |
| without anteriad curvature |
| infranucleate | |
| nucleate |
| 1 lens per eye cup | |
| 3 lenses per eye cup | |
| eye lenses absent |
| absent | |
| present |
| auricles | |
| rounded |
| absent | |
| present |
| absent | |
| present |
| at a distance behind brain | |
| close behind the brain | |
| directly behind the brain |
| postpharyngeal | |
| prepharyngeal | |
| throughout major part of body |
| at anterior end pharynx pocket | |
| at middle pharyngeal pocket | |
| at posterior end phar. pocket |
| 1 | |
| 2 | |
| 3 |
| no | |
| yes |
| common | |
| separate |
| anterior | |
| not applicable | |
| posterior |
| anterior to pharynx | |
| lateral to pharynx | |
| posterior to pharynx |
| in dorsal part of body | |
| in ventral part of body | |
| occupying entire space of body |
| absent | |
| present |
| absent | |
| present |
| absent | |
| present |
| absent | |
| present |