SEGMENTATION n.
mals are derived from the germ cell. In the simplest case, that of small ova destitute of food yolk, the ovum or egg divides into two similar halves or segments (blastomeres), each of these again divides into two, and so on, thus giving rise to a mass of cells (mulberry mass, or morula), all equal and similar, from the…
SESAME n.
is expressed; also, the small obovate, flattish seeds of these plants, sometimes used as food. See Benne. Open Sesame, the magical command which opened the door of the robber's den in the Arabian Nights' tale of "The Forty Thieves;" hence, a magical password. -- Sesame grass. (Bot.) Same as Gama grass.…
SHAD n.
Any one of several species of food fishes of the Herring family. The American species (Clupea sapidissima), which is abundant on the Atlantic coast and ascends the larger rivers in spring to spawn, is an important market fish. The European allice shad, or alose (C. alosa), and the twaite shad. (C. finta), are less impo…
SHELL n.
of marl characterized by an abundance of shells, or fragments of shells. -- Shell meat, food consisting of shellfish, or testaceous mollusks. Fuller. -- Shell mound. See under Mound. -- Shell of a boiler, the exterior of a steam boiler, forming a case to contain the water and steam, often inclosing also flues and t…