YAK n.
vine mammal (Poëphagus grunnies) native of the high plains of Central Asia. Its neck, the outer side of its legs, and its flanks, are covered with long, flowing, fine hair. Its tail is long and bushy, often white, and is valued as an ornament and for other purposes in India and China. There are several domesticated var…
ZONA n.
The outer transparent layer, or envelope, of the ovum. It is a more or less elastic membrane with radiating striæ, and corresponds to the cell wall of an ordinary cell. See Ovum, and Illust. of Microscope. (b) The zona radiata. -- Zona radiata Etym: [NL.] (Biol.), a radiately striated membrane situated next the yolk o…