The microscope body is made of turned ivory. The objective lens and eye lens are mounted in Lignum vitae, and cannot be removed from the body. The eyepiece screws into the base (arrow), but it cannot be unscrewed in this specimen.
The coarse thread at the base is for focusing.
The Lignum vitae topknot acts as a dust cover and is removed to look through the microscope.
Wooden "dust cover" screws into the threaded hole at the top of the microscope.
The front lens is mounted in this wood objective. The outer screw threads have an unknown function.