After fusion the mass solidifies to a transparent vitreous solid which dissolves readily in water to form boric acid (q.v.); it is exceedingly hygroscopic and even on standing in moist air becomes opaque through absorption of water and formation of boric acid.
The simple form of ocellus described in the foregoing paragraph may become folded into a pit or cup, the interior of which becomes filled with a clear gelatinous secretion forming a sort of vitreous Modified after Linko, Travaux Soc. Imp. Nat., St.
The distal portion of the vitreous body may project from the cavity of the cup, forming a non-cellular lens as in Lizzia (fig.
From near the entrance of the optic nerve, through the original choroidal fissure, arises the much-folded pecten, deeply pigmented and very vascular, far into the vitreous humour.
Crystals of azurite belong to the monoclinic system; they have a vitreous lustre and are translucent.