MEDULLARY a.
h unite, making a tube (the medullary canal) from which the brain and spinal cord are developed. -- Medullary rays (Bot.), the rays of cellular tissue seen in a transverse section of exogenous wood, which pass from the pith to the bark. -- Medullary sheath (Anat.), the layer of white semifluid substance (myelin), bet…
MESENTERON n.
All that part of the alimentary canal which is developed from the primitive enteron and is lined with hypoblast. It is distinguished from the stomod, a part at the anterior end of the canal, including the cavity of the mouth, and the proctod, a part at the posterior end, which are formed by invagination and are lined w…