394 GLOSSARY. 



TELSON (Gr. a limit). The last joint in the abdomen of Crustacea; va- 

 riously regarded as a segment without appendages, or as an azygous 

 appendage. 



TENTACULITES (Lat. tentaculum, a feeler). A genus of Pteropoda, 



TEREBRATULA (Lat. tcrebratus, bored or pierced). A genus ot Brachiopoda, so 

 called in allusion to the perforated beak of the ventral valve. 



TEST (Lat. testa, shell). The shell of Mollusca, which are for this reason 

 sometimes called " Teslacea ; " also, the calcareous case of Echinoderms ; 

 also, the thick leathery outer tunic in the Tunicata. 



TESTACEOUS. Provided with a shell or hard covering. 



TESTUDINID.E (Lat. testudo, a tortoise). The family of the Tortoises. 



TETRABRANCHIATA (Gr. tetra, four ; bragchia, gill). The order of Cephalopoda 

 characterised by the possession of four gills. 



TEXTULARIA (Lat. textilis, woven). A genus of Foraminifera. 



THECA (Gr. thekt, a sheath). A genus of Pteropods. 



THECODONTOSAURUS (Gr. thibi, a sheath ; odous, tooth ; saura, lizard). A 

 genus of "Thecodont " Reptiles, so named in allusion to the fact that the 

 teeth are sunk in distinct sockets. 



THERIODONT (Gr. tlierion, a beast ; odous, tooth). A group of Reptiles so 

 named by Owen in allusion to the Mammalian character of their teeth. 



THORAX (Gr. a breastplate). The region of the chest. 



THYLACOLEO (Gr. thulakos, a pouch ; leo, a lion). An extinct genus of Mar- 

 supials. 



TRIGONIA (Gr. treis, three ; gonia, angle). A genus of Bivalve Molluscs. 



TRIGONOCARPON (Gr. treis, three ; gonia. angle ; karpos, fruit). A genus 

 founded on fossil fruits of a three-angled form. 



TRILOBITA (Gr. treis, three ; lobos,a. lobe). An extinct order of Crustaceans. 



TRINUCLEUS (Lat. tris, three ; nucleus, a kernel). A genus of Trilobites. 



TROGONTHERIUM (Gr. trogo, I gnaw ; therion, beast). An extinct genus of 

 Beavers. 



TUBICOLA (Lat. tuba, a tube; and cofo, I inhabit). The order of Annelida 

 which construct a tubular case in which they protect themselves. 



TUBICOLOUS. Inhabiting a tube. 



TUNICATA (Lat. tunica, a cloak). A class of Molluxcoida which are enveloped 

 in a tough leathery case or " test." 



TUKBFNATED (Lat. turbo, a top). Top-shaped ; conical with a round base. 



TCRRILITES (Lat, turris, a tower). A genus of the Ammonitidce. 



UMBO (Lat. the boss of a shield). The beak of a bivalve shell. 



UNGUICULATE (Lat. unguis, nail). Furnished with claws. 



UNGULATA (Lat. ungula, hoof). The order of Mammals comprising the Hoofed 



Quadrupeds. 



UNGULATE. Furnished with expanded nails constituting hoofs. 

 UNILOCULAR (Lat. unus, one ; and loculus. a little purse). Possessing a single 



cavity or chamber. Applied to the shells of Foraminifera and Mollusca. 

 UNIVALVE (Lat. unus, one; valvw, folding-doors). A shell composed of a 



single piece or valve. 

 URODELA (Gr. oura, tail ; delos, visible). The order of the Tailed Amphibians 



(Newts, &c.) 



VENTRAL (Lat. venter, the stomach). Relating to the inferior surface of the 



body. 

 VENTRICULITES (Lat. ventriculum, a little stomach). A genus of siliceous 



Sponges. 



VERMIFORM (Lat. i-ermis, worm ; and forma, form). Worm-like. 

 VERTEBRA (Lat. verto, I turn). One of the bony segments of the vertebral 



column or backbone. 

 VERTEBRATA (Lat. vertebra, a bone of the back, from vertere, to turn). The 



division of the Animal Kingdom roughly characterised by the possession of 



a backbone. 

 VESICLE (Lat. resica, a bladder). A little sac or cyst. 



