GLOSSARY 333 



Sarcode. — The gelatinous material of which the bodies of 



the lowest animals (Protozoa) are composed. 

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



are generally more or less covered, especially in front. 

 Sedimentary Formations. — Rocks 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 colored. 

 Serratures. — Teeth like those of a saw. 

 Sessile. — Not supported on a stem or footstalk. 

 Silurian System. — A very ancient system of fossiliferous 



rocks belonging to the earlier part of the Paleozoic series. 

 Specialization. — The setting apart of a particular organ 



for the performance of a particular function. 

 Spinal Cord. — The central portion of the nervous system 



in the Vertebrata, which descends from the brain through 



the arches of the vertebrae, 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 flowering 



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 skin. 

 Suctorial. — Adapted for sucking. 

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



of which the skull is composed. 



