Definition of terms when describing bats:
Calcar: a cartilaginous structure protruding from the ankle supports the back edge of the interfemoral membrane. The interfemoral membrane acts as a rudder and also reduces oscillations of the body through each wing-beat cycle
Forearm: longest bone in arm, with hook-like thumb at one end.
Keel: flap of skin on edge of tail which is a distinctive projection of the calcar. See a photo of the keel and calcar on Wikipedia.
Total length: measured from nose tip to tail tip.
Premolars: are the teeth with points, just behind the canine. Molars are further back and are relatively flat.
Tragus: a projection surrounded by external ear flap, often stiffened with cartilage. Ours is a little blunt one, in front, center of ear, forming front of entrance to ear canal.