.Most virions are roughly spherical (about 200nm in diameter) but they can be much larger and more pleomorphic.
The virus envelope is a lipid bilayer, studded with virus encoded glycoproteins which have
properties of haemagglutination
and fusion (the F protein).

By transmission electron microscopy, and negative staining, the helical ribonucleo-protein capsid has a "herring-bone" appearance.