Bird vision other vertebrates. The outer layer of the eye consists of the transparent cornea at the front, and two layers of sclera — a tough white collagen fibre layer which surrounds the rest of the eye and supports and protects the eye as a whole. The eye is divided internally by the lens into two main segments: the anterior segment and the posterior segment. The anterior chamber is filled with a watery fluid called the aqueous humour, and the posterior chamber contains the vitreous humour, a clear jelly-like substance. The lens is a transparent convex or 'lens' shaped body with a
The Layer Quaternity The Layer Quaternity The Layer Quaternity are four marble sculpture figurines approximately in height located on the two columns of the Layer Monument, an early 17th-century polychrome mural monument () which was installed in the Church of Saint John the Baptist, Maddermarket, Norwich to the memory of Christopher Layer (1531–1600). The quartet of figurines sculptured in marble, "Pax, Gloria, Vanity, Labor" exhibit primary thematic concerns and stylistic attributes of Northern Mannerist art, namely, portraiture of animated human movement, variety and multiplicity, often set in the Classical or mythological world, and inclined towards esoteric concepts. The Layer Quaternity ("circa" 1598–1604) share