GLOSSARY 



687 



ally protected by a resistant covering and is 

 capable of developing independently into a 

 new individual. 



Spor'u-la"tion (Gr. spora, seed). Process of 

 forming spores; reproduction by multiple 

 fission. 



Squa-mo'sal (L. squamosus, scaly). T-shaped 

 bone of the skull of a vertebrate, bracing the 

 posterior end of the jaws. 



Stat'o-cyst (Gr. statos, stationary; kystis, sac). 

 Organ of equilibrium in animals such as the 

 crayfish. 



Stat'o-lith (Gr. statos, standing; lithos, stone). 

 A solid body within a statocyst. 



Ste-ap'sin (Gr. stear, tallow; pepsis, digest). 

 An enzyme of the pancreas that acts on fats. 



Ster'num (L., breastbone). Bone or bones of 

 the ventral side of the thorax of a vertebrate; 

 breastbone. 



Stig'ma (Gr., pricked mark). A sensitive pig- 

 ment or eye spot in certain Protozoa. 



Stim'u-lus (L. stimulare, to incite). A change 

 in the external or internal environment of an 

 animal that brings about a response. 



Stra'ti-fied (L. stratum, covering). Arranged 

 in layers, one above the other. 



Stra'tum com-pac'tum (L. stratum, covering. 

 L. cum, with; pangere, to fasten). Inner 

 laver of the corium or dermis of the skin. 



Stra'tum cor'ne-um (L., covering. L. corneus, 

 horny). Outer layers of cells in the epider- 

 mis of the skin of a vertebrate. 



Stra'tum ger'mi-na-ti"vum (L., covering. L. 

 germinare, to sprout). Mitotic layer of cells 

 in the epidermis of the skin of a verte- 

 brate. 



Stra'tum spon-gi-o'sum (L., covering. Gr. 

 spongos, sponge). Outer layer of connective 

 tissue in the dermis (corium) of a verte- 

 brate. 



Stri'at-ed (L. stria, channel). Cross striped, as 

 one of the principal types of muscle cells. 



Sub-cla'vi-an (L. sub, under; clavis, clavicle). 

 Under the collarbone (clavicle); it refers to 

 a particular muscle, blood vessel, or other 

 structure in this region. 



Sub-cu-ta'ne-ous (L. sub, under; cutis, skin). 

 Just beneath the skin, as subcutaneous con- 

 nective tissue. 



Sul'cus (L. sulcus, furrow). A fissure or groove. 



Su'ture (L. sutura from suere, sutum, to sew). 

 Line of fusion between 2 bones. 



Swim'mer-et (A.S. swima, swoon). An ab- 



dominal appendage that functions as a 

 swimming organ. 



Sym'bi-o"sis (Gr. syn, together; hios, life). 

 Living together of two different species of 

 organisms. Symbiosis is best used as an in- 

 clusive term to cover mutualism, commensal- 

 ism, and parasitism. 



Sym'me-try (Gr. syn, together; meton, meas- 

 ure). The state of being symmetrical; an 

 organ is said to possess symmetry if it can be 

 divided by a line or plane into two parts 

 which are essentially similar. 



Syn'apse (Gr. syn, together; hapto, unite). 

 The region of communication between neu- 

 rons; the point at which an impulse passes 

 from an axon of one neuron to a dendrite of 

 another. 



Syn-ap'sis (Gr. synapsis, contact). The tem- 

 porary union of homologous chromosomes 

 (maternal and paternal) previous to the first 

 maturation division. 



Syn-cyt'i-um (Gr. syn, togther; kytos, cell). An 

 undi\idcd mass of cytoplasm containing 

 many nuclei. It is a product of nuclear divi- 

 sion without cell division. 



Sys'tem (Gr. syn, together; histanai, to place). 

 A group of organs concerned with the same 

 general function, as circulation or diges- 

 tion. 



Sys-tem'ic arch (Gr. systema, placing together. 

 L. arcus, bow). Any large artery of a verte- 

 brate, carrying blood from the heart to the 

 dorsal aorta. 



Tac'tile (L. tangere, to touch). Pertaining to 

 the sense of touch. 



Tar'sals (Gr. tarsos, flat of the foot). Bones 

 of the ankle. 



Tar'sus (Gr. tarsos, flat of the foot). The distal 

 end of the leg of an insect; it consists of one 

 or more segments, the most distal bearing 

 claws. An ankle bone of vertebrates. 



Tax-on'o-my (Gr. taxis, arrangement; nomas, 

 law). The science that deals with the classi- 

 fication of organisms. 



Tel'e-or'o-gy (Gr. telos, end; logis, study). An 

 unscientific method of thinking. The use of 

 purpose in which a result is treated as a cause 

 in tlic explanation of natural phenomenon. 



Td'o-phase (Gr. telos, end; phasis, aspect). 

 Any of the final phases of mitosis in which 

 the cell divides and the daughter nuclei are 

 formed. 



