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(1) In man and other mammals, the fold or prominence at the base of the pinna. The tragus is maximally developed in some bats. It is possible that the tragus serves as a supplementary screen to concentrate and direct the sound reaching the ear. When maximally developed, the tragus is part of the spatial hearing mechanism and helps to amplify the biologically most important sound frequencies.
(2) In birds, the tragus is the pyramidal bony or cartilaginous prominence at the junction of the inner bronchial walls (inferior larynx). It is possible that it may be used in sound transmission.
a genus of annual or perennial herbs of the family Gramineae. The stems are spread out at the base and take root at the nodes. The leaf blades are stiff, short, and usually flat. The inflorescence is a spicate panicle with very short branches; the spikelets are one-flowered. The leathery upper glume, which is equal to the spikelet in length, has large, hooked thorns along the veins. There are six to ten species, distributed in subtropical, tropical, and warm-temperate regions of both hemispheres. The plants occur mainly in Africa. The USSR has one species, T. racemosus. An introduced plant, it is found in the southern European USSR, the Caucasus, and Middle Asia. T. racemosus grows in sandy and gravelly places, on rocky slopes, along roads, and as a weed in fields.