The hard lower surface of the head is called the gula (hypostomal bridge).
The turtle ear has an eardrum flush with the surface of the head.
With some guys (and most of those whose heads contain the Jersey Deposit formation are men, curiously), a gas seep rises clear to the surface of the head.
The tympanum, usually exposed at the surface of the head or at the end of a short open tube, may be covered by scales or may be absent.
The pollen itself is freely exposed on the surface of the head, and a single head is likely to be visited by several kinds of insects.
"Like an electroencephalogram, which measures brain activity by electrodes distributed over the surface of the head, we have sensors around the world, measuring the human population as a whole," said Mr. Nelson.
Each pit is a cavity about 1 5 mm (0.04 0.2 inches) deep, equally as wide at the bottom, and narrowing toward the opening at the surface of the head.
All, however, show drastic ear modifications that reflect their early history as burrowers; for example, there is no external ear i.e., no opening at the surface of the head for the entrance of sound.
Skates, which sometimes hold the lower surface of the head slightly above the bottom, may inhale some water through the mouth; mantas, which have small spiracles and live near the surface, respire chiefly through the mouth.
Further, while headgear protects a fighter from facial cuts, some observers think it increases a fighter's chance of incurring brain damage because it enlarges the hitting surface of the head and thereby makes the head an easier target.
Measurement points were located on the surface of the head, chest, hip, thigh, shin, upper arm and lower arm.
