Perennibranchiata :: Perennibranchiata (n. pl.) Those Batrachia which retain their gills through life, as the menobranchus..
Perennibranchiate :: Perennibranchiate (a.) Having branchae, or gills, through life; -- said especially of certain Amphibia, like the menobranchus. Opposed to caducibranchiate..
Quadrennium :: Quadrennium (n.) A space or period of four years.
Rennin :: Rennin (n.) A milk-clotting enzyme obtained from the true stomach (abomasum) of a suckling calf. Mol. wt. about 31,000. Also called chymosin, rennase, and abomasal enzyme..