Arach´noid, n. One of the three enveloping membranes of the brain, between the dura mater and the pia mater.
Arbor´icole, a. Tree-inhabiting.
Arch´etype, n. Original plan or idea of structure, modified or lost by subsequent specialization.
Archetyp´ical, a. Having the primitive pattern or original plan of structure.
Arc´uate, a. Bow-shaped; bent regularly and gradually.
Are´ola, n.; pl. areolæ. Small naked space on the feet between scales.
Are´olar Tissue. The light cellular connective tissue of the body.
Armil´la, n. Ring of color, like a bracelet, around lower end of crus.
Arm´pit, n. (78.) See Axilla.
Arte´rial, a. Pertaining to arteries; as, arterial system, arterial blood.