The papillæ filiformes

cover the anterior two-thirds of the dorsum. They are very minute, filiform in shape, and arranged in lines parallel with the two rows of the papillæ vallatæ, excepting at the apex of the organ, where their direction is transverse. Projecting from their apices are numerous filamentous processes, or secondary papillæ these are of a whitish tint, owing to the thickness and density of the epithelium of which they are composed, which has here undergone a peculiar modification, the cells having become cornified and elongated into dense, imbricated, brush-like processes. They contain also a number of elastic fibers, which render them firmer and more elastic than the papillæ of mucous membrane generally. The larger and longer papillæ of this group are sometimes termed papillæ conicæ.

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