Sirenia

**Definition:** An order of heavy-bodied, slow-moving, completely aquatic, herbivorous mammals. The body is fusiform, plump, and hairless, except for bristles on the snout. Hindlimbs are absent, the forelimbs are modified to flippers, and the tail is a horizontal fluke. (From Scott, Concise Encyclopedia Biology, 1996)

**Tree numbers:** - B01.050.150.900.649.313.250.750