Salivary glands. Glands in many terrestrial animals that secrete saliva into the mouth. In man there are three pairs: sublingual, submandibular, and the submaxillary glands. The salivary gland cells of some insect larva produce giant (polytene) chromosomes, which are widely used in the study of genetics and protein synthesis.

Salt gland. A hydathode that secretes a saline solutions.

Sarcoma. A cancerous growth derived from muscle, cartilage or connective tissue.

Sarcoplasm. The cytoplasm of a muscle cell.

Scabrous. Having a rough surface.

Scape. A flower stalk bearing no leaves and arising from a rosette of leaves.

Sacpula. Dorsal part of shoulder girdle. Shoulder-blade in man and other mammals.

Schizogenous. (Of secretory cavities in plants), originating by separation of cells, e.g. oil-containing cavities in leaves of St. John’s wort. Cf. lysigenous.

Sclerotic. Fibrous or cartilaginous firm outer coat of eyeball in vertebrates, continuous with cornea in front of eye.

Sclerotium. Compact tissue-like mass of fungus hyphae, often with a thickened rind, varying in size from that of a pin’s head to that of a man’s head; capable of remaining dormant for a long periods, e.g. during conditions unfavourable to normal fungus growth, and commonly giving rise to fruit bodies, e.g. ergot.

Scrub. A habitat in which shrubs predominate.

Scypho. Denoting a bowl or cup-like structure.

Secretin. A hormone responsible for the secretion of bile from the liver second. All turned to one side.

Scyphistoma. The fixed (polyp) stage of jellyfish (scyphozoan Coelenterata), usually quite small and insignificant, which by horizontal splitting gives rise to free-swimming jellyfish.