GLOSSARY 553 



So'ma (Adjective, somatic) (Gr. soma, a body): the part of the organism limited to its 



individual life; non-reproductive. 

 Sperm (Gr. sperma, from speiro, sow): the male element in sexual reproduction. 

 Sphinc'ter (Gr. sphiggo, bind tight): a circular band of muscle which closes an aperture 



by its contraction. 

 Spu'tum (Lat. sputus, from spuo, spit): expectorated matter characteristic of certain 



diseases. 

 Steap'sin: a digestive ferment found in the pancreatic juice which assists in the di- 

 gestion of fats. 

 Ster'ile (Lat. sterilis, barren): free from bacteria of every kind; infertile. 

 Stig'ma (Gr. stigma from stizo, prick): any agent that excites to organic action. 

 Stom'ach (Gr. stomachos from stoma, mouth): the sac or enlarged portion of the di- 

 gestive tract between the esophagus and intestine. 

 Sucto'ria (Lat. suctus, from sugo, suck): an order of insects which have sucking mouths, 



as fleas. 

 Su'ture (Lat. sutura, from siio, sew): the joining of two bones by mutually serrated 



edges, forming an immovable articulation, as in the bones of the skull. 

 Symbio'sis (Gr. syn, together; bios, life): the close relationship of two organisms for 



mutual benefit. 

 Tar'sus (Gr. tarsos, any flat surface): the ankle; the scaly part of a bird's leg; the 



terminal segment of an insect's foot. 

 Ten'don (Lat. tendo, stretch): the connective tissue ending of a muscle which attaches 



it to other structures. 

 Ten'tacle (Lat. tento, touch, try): a jointed flexible appendage of the head used for 



touch, grasping, or motion; a feeler. 

 Tes'tis (Lat. testis, a testicle): an organ in a male animal where sperms are produced. 

 Thy'roid (Gr. thureos, shield; eidos, form) gland: a large ductless gland on the outside 



of the trachea below the larynx which secretes thyroxin (C15H11O4NI4). 

 Tra'chea (Gr. tracheia, windpipe): the air passage from the pharynx to the lungs; an 



air tube in insects and spiders. 

 Tra'cheole (dim. oi tr aches): one of the fine branches of the Tracheae. 

 Trichinel'la (Gr. thrix, hair): a small round worm sometimes found in pork living as a 



parasite, and the cause of trichinosis in man. 

 Tri'chocysts (Gr. thrix, hair; kystis, bag): dart-like organs of offense and defense found 



in Paramecium. 

 Tro 'chanter (Gr. trochanter, from trecho, run): the second joint of an insect's leg. 

 Tryp'sin (Gr. tripsis, a rubbing): an enzyme of the pancreatic juice. 

 Tur'gid (Lat. turgeo, swell): distended with air or liquid; swollen. 

 Ungula'ta (Lat. unguis, nail): a group of mammals characterized by hoofs. 

 Ure'a (Gr. oiiron, urine): a nitrogenous compound (CO(NH2)2), the chief waste product 



discharged in mammalian urine. 

 Ure'ter (Gr. oureter, from ouron, urine): a tube, one of two, leading from the kidneys to 



the bladder and carrying off the nitrogenous waste in the urine. 

 U'ropod (Gr. oura, tail; pod, from pous, foot): the modified swimmerets on either side of 



the last segment of a crayfish. These, together with the telson (the modified last 



segment), make up an appendage useful in swimming backwards. 

 Ven'tricle (Lat. ventriculus, a little belly): one of the lower chambers of the heart. 



