GLOSSARY 



mos, law). The science of the classifi- 

 cation of living things. 

 Tero-phase (Gr. tdos, end; phasis, aspect). 



The last stage in mitotic division. 

 Ten'don (L. tendere, to stretch). A fibrous 

 cord of connective tissue w^hich binds 

 a muscle to a bone or to odier struc- 

 tures. 

 Ten'ta-cle (L. tentare, to touch, feel). A 

 slender, whip-like organ for feeling or 

 motion found in invertebrates. 

 Ter-res'tri-al (L. terra, earth). Living on 



the ground. 

 Tes'tis (L. testis). The sperm-forming male 



gonad. 

 Tet'rad (Gr. tetra, four). The four chromo- 

 somes which arise during maturation 

 from the pairing and splitting of a 

 homologous pair of chromosomes. 

 The'o-ry (Gr. theoria, a beholding, specu- 

 lation). A formulated hypothesis. 

 Tho-rac'ic (Gr. thorax, chest). Pertaining to 



the chest or thorax. 

 Tho'rax (Gr. chest). The chest. 

 Throm'bin (Gr. thrombos, clot). A sub- 

 stance produced in shed blood when 

 prothrombin comes in contact with 

 thromboplastin. It is essential in clot 

 formation. 

 Throm'bo-plas"tin (Gr. thrombos, clot; 

 plastikos, to form, mold). A substance 

 released from injured cells or platelets 

 , that initiates blood clotting. 

 Thy'mus (Gr. thtjmos, thymus). A ductless 

 gland-like body situated ventral and 

 anterior to the heart and below the 

 thyroid. 

 Thy'roid ( Gr. thyreos, shield; eidos, resem- 

 ble ) . An endocrine gland located in the 

 neck of vertebrates which secretes thy- 

 roxine. 

 Thy-rox'ine. The hormone secreted by the 



thyroid. 

 Tis'sue (L. texere, to weave). A collection 

 of cells, usually similar, organized for 

 the performance of a specific function. 

 Tox'in (Gr. toxicon, poison). A poisonous 

 substance of plant or animal origin. 



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Tra'che-a (Gr. tracheia, windpipe). The 

 breathing tube or windpipe of verte- 

 brates and the tiny air tubes of certain 

 arthropods. 



Trait (L. tractus, a drawing). An inherited 

 character. 



Trip'Io-blas"tic (Gr. triplax, triple; blastos, 

 bud). Having three germ layers. 



Tryp'sin ( Gr. triiein, rubbing down; pepsis, 

 digesting). A protein-splitting pan- 

 creatic enzyme. 



Tym-pan'ic mem'brane (Gr. tijmpanon, 

 eardrum; L. membrana, skin cover- 

 ing). The eardrum. 



Um-biri-cal cord (L. umbilictts, navel). 

 The cord-like connection between the 

 placenta and the fetus of mammals. 



U-re'a (Gr. oiiron, urine). A nitrogenous 

 metabolic waste of mammals found in 

 urine. 



U're'ter (Gr. otireter, ureter). The tube 

 which carries urine from the kidney to 

 the bladder or to the cloaca. 



U-re'thra (Gr. otireter, ureter). The tube 

 that carries urine from the bladder to 

 the surface, and in the male conveys 

 the seminal fluids. 



U'rine ( L. urina, urine ) . The fluid secreted 

 by the kidney. 



U'rin-if'er-ous tu'bule (L. urina, urine; 

 ferre, to bear; tiibidus, any small tube ) . 

 One of the excretory tubules in the kid- 

 ney of higher vertebrates, consisting of 

 a cofled tube and a capsule. 



U'ro-gen"i-tal ( u'ri-no-gen"i-tal sys'tem) 

 (Gr. oiiron, urine; gignesthai, to pro- 

 duce ) . Pertaining to both the excretory 

 and reproductive systems. 



U'ter-us (L. womb). The hollow muscular 

 posterior end of the oviduct where 

 the developing animal is contained and 

 nourished. 



Vac'u-ole (L. vacuum, empty). Small space 

 in the cytoplasm. 



