| Using the retractile method has had the unanticipated benefit of allowing school classes to stand on the bridge and ride it as it slides open. |
| The feeding zooids use retractile tentacles, called the lophophore, to filter feed and have a U-shaped gut for digestion. |
| The habit of felids to use primarily their forelimbs to capture prey is supported by the anatomy and function of their retractile claws. |
| If a testis is not palpable, it is important to determine if it is retractile, ectopic, or cryptorchid. |
| Spores may be demonstrated by phase-contrast microscopy of wet mounts, where they appear mature and retractile. |
| Ten circumoral appendages are present, the 4th being the longest pair, and is retractile into pockets at the ventrolateral sides of head. |
