| The dorsal fin is thick and falcate in nature, and is located about a third of the way down the length of the animal. |
| In the genus Pontoporia the dorsal fin is well developed and falcate. |
| Front outer angle of each front wing projecting into a falcate tip. |
| The dorsal fin was relatively small, falcate, and obtusely terminated. |
| Beaked whales have a small, falcate dorsal fin, which is set fairly far back on their bodies. |
| Prickles straightish or falcate, slender or strong, without bristles. |
