STALACt.i.tES (Gr. _stala.s.so_, I drop). Icicle-like encrustations and deposits of lime, which hang from the roof of caverns in limestone.

STALAGMITE (Gr. _stalagma_, a drop). Encrustations of lime formed on the floor of caverns which are hollowed out of limestone.

STIGMARIA (Gr. _stigma_, a mark made with a pointed instrument).

A genus founded on the roots of various species of _Sigillaria_.

STRATUM (Lat. _stratus_, spread out; or _stratum_, a thing spread out). A layer of rock.

STROMATOPORA (Gr. _stroma_, a thing spread out; _paras_, a pa.s.sage or pore). A Palaeozoic genus of _Protozoa_.

STROPHOHENA (Gr. _strophao_, I twist; _mene_, moon). An extinct genus of Brachiopods.

SUB-CALCAREOUS. Somewhat calcareous.

SUB-CENTRAL. Nearly central, but not quite.

SUTURE (Lat. _suo_, I sew). The line of junction of two parts which are immovably connected together. Applied to the line where the whorls of a univalve sh.e.l.l join one another; also to the lines made upon the exterior of the sh.e.l.l of a chambered _Cephalopod_ by the margins of the septa.

SYRINGOPORA (Gr. _surigx_, a pipe; _poros_, a pore). A genus of Tabulate Corals.

TABULae. (Lat. _tabula_, a tablet). Horizontal plates or floors found in some Corals, extending across the cavity of the "theca"

from side to side.

TEGUMENTARY (Lat. _tegumentum_, a covering). Connected with the integument or skin.

TELEOSAURUS (Gr. _teleios_, perfect; _saura_, lizard). An extinct genus of Crocodilian Reptiles.

TELEOSTEI (Gr. _teleios_, perfect; _osteon_, bone). The order of the "Bony Fishes."

TELSON (Gr. a limit). The last joint in the abdomen of _Crustacea_; variously regarded as a segment without appendages, or as an azygous appendage.

TENTACULITES (Lat. _tentaculum_, a feeler). A genus of _Pteropoda_.

TEREBRATULA (Lat. _terebratus_, bored or pierced). A genus of _Brachiopoda_, so called in allusion to the perforated beak of the ventral valve.

TEST (Lat. _testa_, sh.e.l.l). The sh.e.l.l of _Mollusca_, which are for this reason sometimes called "_Testacea_;" also, the calcareous case of _Echinoderms_; also, the thick leathery outer tunic in the _Tunicata_.

TESTACEOUS. Provided with a sh.e.l.l or hard covering.

TESTUDINIDae (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. _theke_, a sheath). A genus of Pteropods.

THECODONTOSAURUS (Gr. _theke_, 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. _therion_, 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 Marsupials.

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 _colo_, 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 cla.s.s of _Molluscoida_ which are enveloped in a tough leathery case or "test."

TURBINATED (Lat. _turbo_, a top). Top-shaped; conical with a round base.

TURRILITES (Lat, _turris_, a tower). A genus of the _Ammonitidoe_.

UMBO (Lat. the boss of a shield). The beak of a bivalve sh.e.l.l.

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

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

UNGULATE. Furnished with expanded nails const.i.tuting hoofs.

UNILOCULAR (Lat. _unus_, one; and _loculus_. a little purse).

Possessing a single cavity or chamber. Applied to the sh.e.l.ls of _Foraminifera_ and _Mollusca_.

UNIVALVE (Lat. _unus_, one; _valvoe_, folding-doors). A sh.e.l.l 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. _vermis_, worm; and _forma_, form). Worm-like.