GLOSSARY 551 



Mim'icry (Gr. mimikos, imitative): resemblances in form or color shown by some 

 organisms to other objects, to protect themselves. 



Mito'sis (Gr. mitos, thread): the processes in typical nuclear division. 



Mollusks (Lat. mollis, soft): a group of animals having soft bodies, usually covered by 

 one or two shells. 



Morphol'ogy (Gr. morphe, form; logos, discourse): study of structure and form. 



Motor (Lat. moveo, move) fibers: nerve fibers which convey impulses to the muscles, 

 producing motion. 



Mu'cous (Lat. mucus, slime) membrane: the lining of the alimentary canal and respira- 

 tory tract. 



My'osin (Gr. myo, muscles): the form of protein found in muscle. 



Myriop'oda (Gr. myrioi, ten thousand; /)o«j, foot): a group of crustaceans having four 

 legs on each segment. 



Neuroblast (Gr. neuron, sinew; blastos, germ): an embryonic nerve cell. 



Neu'ron (Gr. neuron, sinew): a nerve cell with all its processes. 



No'tochord (Gr. notos, the back; chorde, a string): a rod of cells in all vertebrate em- 

 bryos. 



Nour'ishment (Lat. nutrio, nurse or feed): growth-promoter; food. 



Nu'cleus (Lat. nucleus, a kernel): specialized protoplasm. 



Nutri'tion (Lat. nutrio, nurse or feed): that which promotes growth. 



Odona'ta (Gr. odontos, toothed): an order of insects, including dragon flies and damsel 

 flies. 



Oesoph'agus (esophagus) (Gr. oiso, will bear; phagein, to eat): the alimentary canal 

 between the pharynx and stomach. 



Oper'culum (Lat. operculum, lid): the gill cover in fishes. 



Optic (Gr. optikos, sight) nerve: nerve which conducts stimuli from retina to brain. 



Or'ganism (Gr. organon, instrument): a living body. 



Or'thogen'esis (Gr. orthos, straight; genesis, descent): evolution in a definite direction. 



Orthop'tera (Gr. orthos, straight; pteron, wing): a group of insects whose outer wings 

 meet in a straight line in the middle of the back, as grasshoppers and crickets. 



Osmo'sis (Gr. osmos, pushing): the passing of soluble substances through a moist 

 membrane, the greater movement being towards the denser liquid. 



Par'asite {Gr. para, beside; sitein, to feed): an animal or plant which lives upon another 

 living organism injuring its host. 



Parathyroid (Gr. para, beside): a small ductless gland near the thyroid controlling the 

 calcium metabolism of the body. 



Pec'toral (Lat. pectus, breast) girdle: the bones which support the anterior limbs of 

 vertebrates and attach them to the trunk. 



Pericar'dium {Gr. peri, around; cardia, heart): the membranous sac inclosing the heart. 



Perios'teum (Gr. peri, around; osteon, bone): the membrane which adheres to and 

 covers the bones. 



Peristal'sis (Gr. peri, around; stalsis, constriction): the squirming motion in the in- 

 testine caused by its muscles. 



Perspira'tion (Lat. per, through; spiro, breathe): the watery secretion of the per- 

 spiratory glands. 



Pha'gocytes (Gr. phagein, to eat; cytos, sac): the white corpuscles of the blood which 

 act as scavengers. 



