320 GLOSSARY. 



the cud, siTch as oxen, sheep, and deer. They have divided 

 hoofs, and are destitute of front teeth in the upper jaw. 



Sacral. — Belonging to the sacrum, or the bone composed usually 



of two or more united vertebraj to which the sides of the pelvis 



in vertebrate animals are attached. 

 Sarcode. — The gelatinous material of which the bodies of the 



lowest animals (Protozoa) are composed. 

 ScuTELL^. — The horny plates with wliich the feet of birds are 



generally more or less covered, especially in front. 

 Sedimentary Formatioks. — Kocks deposited as sediments from 



water. 

 Segments. — The transverse rings of which the body of an articulate 



animal or Annelid is composed. 

 Sepals. — The leaves or segments of the calyx, or outermost envelope 



of an ordinary flower. They are usually green, but sometimes 



brightly coloured. 

 Serratuhes. — Teeth like those of a saw. 

 Sessile. — Not supported on a stem or footstalk. 

 Silurian System. — A very ancient system of fossiUferous rocks 



belonging to the earlier part of the PahTOzoic series. 

 Specialisation. — The setting apart of a particular organ for the 



performance of a particular function. 

 Spinal Chord. — The central portion of the nervous system in tho 



Vertebrata, which descends from the brain through the .arches 



of the vertebra^, and gives off nearly all the nerves to the various 



organs of the body. 

 Stamens. — The male organs of flowering plants, standing in a circle 



within the petals. They usually consist of a filament and an 



anther, the anther being the essential part in which the pollen, 



or fecundating dust, is formed. 

 Sternum. — The breast-bone. 



Stigma. — The apical portion of the pistil in flowerin':: plants. 

 Stipules. — Small leafy organs placed at the base of the footstalks 



of the leaves in many plants. 

 Style. — The middle portion of the perfect pistil, which rises like a 



column from the ovary and supports the stigma at its summit. 

 Subcutaneous. — Situated beneath the skia. 

 Suctorial. — Adapted for sucking. 

 Sutures (in the skull). — The hues of junction of the bones of which 



the skull is composed. 



