1. The coleoptile of the seedling in Gramineæ is the basal part of the cotyledon. The middle part of the cotyledon turns dowdward immediately from the cotyledonary node and together with the hypocotyl forms the mesocotyl. The upper part of the cotyledon turns again upward from the point near the transition plate (the first node of seedling) and forms the scutellum which covers other embryonal parts, namely the plumule, the coleoptile, the primary root etc. 2. In almost all plants in Gramineae, scutellum trace (the bundle of cotyledon in its middle part) and the stele of hypocotyl run parallel as two independent bundles, but in Zea Mays they are fused to form a compound-stele of mesocotyl. 3. The cotyledon is not to be considered as a terminal structure, but lateral one, while the growing point of the plumule is the terminal one in view of the structure of bundles in the mesocotyl-stele. The present writer grees with AVERY in that she considers the scuttellum, a part of cotyledon, is a lateal structure, while she does not agree with him in that the coleoptile is a terminal structure.