The
ENVELOPE that surrounds the nucleocapsid is derived from the inner nuclear
membrane of the host cell.
Virus-encoded glycoproteins
are incorporated into the virion envelope and are visible as "spikes"
that project from its surface.
In the micrograph of HSV, the glycoprotein B (gB) is clearly visualised in
clusters of spikes appoximately 10 nm in length.
Between the capsid and the envelope is an ill-defined layer of proteins, collectively known as the tegument.



Herpesviruses have an
envelope surrounding an icosahedral capsid, approximately 100nm in diameter,
which contains the dsDNA genome.
When the envelope breaks and collapses away from the capsid, negatively stained
virions have a typical "fried-egg" appearance.
The herpes virus CAPSID is an icosahedron of triangulation number T = 16. There are 12 pentavalent capsomers (one at each apex) and 150 hexavalent capsomers. Each capsomer has a deep central indentation.
