Within the Mysticeti (baleen whales), are the Gray, Blue, Humpback, and Right whales. These whales are usually larger but slower than the Odontoceti.
Within the Odontoceti (toothed whales), are the Sperm, Orca, Beluga, and Narwhal whales. In contrast to the baleen whales, they are smaller (though the Sperm whale is quite large) but faster.
Cetaceans have two side fins, flukes (flipper-like tails), and blowholes (two blowholes for baleen whales, and one blowhole for toothed whales); some have dorsal fins (but not all).