白鳍豚的外形用英语怎样描述

Baiji was a freshwater white dolphin found only in the Yangtze River in China. Dolphins have a streamlined fusiform body, adapted for fast swimming. The tail fin is used for propulsion while the pectoral fins, together with the entire tail section, provide directional control.
The head contains the melon, a round organ used for echolocation. its elongated jaws form a distinct beak with have a curved mouth which looks like a fixed smile. Baijis breathe through a blowhole on top of their head. The trachea is anterior to the brain. The Baiji's brain is large and highly complex.