142 GLOSSARY. 



Tape'tum (L. drapery, carpet). The shining layer existing in 



the choroid coat of the eye in some animals. Also a layer 



of fibres upon the surface of the lateral ventricles of the 



brain. 

 Tar'digrada (L. tarde, slowly; gradus, a step). A group of 



the Phytophagous Edentata which comprises the sloths. 

 Tar'sal cartilages (L. tarsus, the cartilage supporting the eye). 



Cartilages placed one in each eyelid to give firmness to 



those parts. 

 Tarsa'lia (Gr. tarsos, the flat of the foot). The bones of the 



tarsus. 

 Tar'so-me'tatarsus. The ankylosed tarsus and metatarsus in 



birds. 

 Tar'sus (Gr. tarsos, the flat of the foot). That part of the 



posterior extremity in the Vertebrata which intervenes 



between the crus and the metatarsus, and which in man 



forms the ankle. Also the fifth segment of the leg in the 



Insecta. 

 Taurocho'lic acid (Gr. tauros, a bull; chole, bile). An acid 



found in the bile of the ox, and also largely in that of man. 

 Taxo'nomy (Gr. taxis, arrangement, order). That division of 



the science of Biology which treats of the classification 



of animals and plants according to their structural charac- 

 teristics. 

 Tecto'rial mem'brane (L. tectdrius, used for covering). A 



membrane connected with the organ of Corti in the 



internal ear. 

 Tegmen'tum of cru'ra ce'rebri (L. tegmentum, a covering). The 



fibres forming the upper part of the peduncle of the brain. 

 Te'la choroi'dea (L. choroid web). Another name for the 



velum interpositum which connects the choroid plexuses 



of the two sides of the cerebrum together. 

 Teleology (Gr. telos, an end accomplished ; logos, a discourse). 



The study of function. 

 Teleos'tei (Gr. teleos, complete, whole). A division of the class 



Pisces, comprising the so-called osseous (bony) fishes. 

 Telosau'ridae (Gr. telos > the end, limit; sauros, a lizard). 



A group of the Crocodilia, extinct and of pre-cretaceous age. 

 Telotro'cha (Gr. telos, the end, limit ; trochos, anything round). 



A name given to certain Annelidan larvae. 

 Tem'poral (L. tempora, the temples). The name of each of a 



pair of bones in the skull ; also of the arteries, nerves, and 



veins supplying that portion of the skull. 



