| Answer | Crossword Clue |
|---|---|
| SCUBA | Apparatus with a harness and flippers |
| SKINDIVING | Activity with a mask and flippers |
| frogmen | a person equipped (as with face mask, flippers, and air supply) for extended periods of underwater swimming |
| ichthyosaurs | An extinct marine reptile of the Mesozoic era resembling a dolphin, with a long pointed head, four flippers, and a vertical tail |
| ichthyosaur | An extinct marine reptile of the Mesozoic era resembling a dolphin, with a long pointed head, four flippers, and a vertical tail |
| penguin | A large flightless seabird of the southern hemisphere, with black upper parts and white underparts and wings developed into flippers for swimming under water |
