Another important part of their bodies comes in pennaceous and down varieties.
These animals have a vocal organ called the syrinx, and their lymphatic system includes the Bursa of Fabricus. Another important part of their bodies comes in pennaceous and down varieties. Discovered in Solnhofen, Germany, the extinct Archaeopteryx is believed to be the most primitive species of these due to the fact that it had feathers. For 10 points, name this modern class of vertebrates, examples of which include the flightless emu and flying eagles.
These animals have a vocal organ called the syrinx, and their lymphatic system includes the Bursa of Fabricus.
{birds} [accept {Aves}]