GLOSSARY. 393 



Sessile (Lat. sedo, I sit). Not supported upon a stalk or peduncle; attached 



by a base. 

 Set^ (Lat. bristles). Bristles or long stiff hairs. 

 SiGiLLARioiDS (Lat. sigilla, little images). A group of extinct plants of which 



Sigillaria is the type, so called from the seal-like markings on the bark. 

 Siliceous (Lat. silex, flint). Composed of flint. 



Sinistral (Lat. sinistra, the left hand). Left-handed ; applied to the direc- 

 tion of the spiral in certain shells, which are said to be " reversed." 

 Siphon (Gr. a tube). Applied to the respiratory tubes in the Mollusca ; 



also to other tubes of diff'erent functions. 

 SiPHONiA (Gr. siphon, a tube). A genus of fossil Sponges. 

 SiPHONOSTOMATA (Gr. siphon ; and stoma, mouth). The division of Gastero- 



podous Molluscs in which the aperture of the shell is not " entire," but 



possesses a notch or tube for the emission of the respiratory siphon, 

 SiPHUNCLE (Lat. siphuncuhis, a little tube). The tube which connects to- 

 gether the various chambers of the shell of certain Cephalopoda {e.g., the 



Pearly Nautilus). 

 SiRENiA (Gr. seiren, a mermaid). The order of Mammalia comprising the 



Dugongs and Manatees. 

 SiVATHERiUM (Siva, a Hindoo deity ; Gr. therion, beast). An extinct genus 



of Hoofed Quadrupeds. 

 SOLIDUNGULA (Lat. soUdics, solid ; ungula, a hoof). The group of Hoofed 



Quadrupeds comprising the Horse, Ass, and Zebra, in which each foot has 



only a single solid hoof. Often called Solipedia. 

 Sphenopteris (Gr. sphen, a wedge; pteris, a fern). An extinct genus of 



ferns. 

 Spicula (Lat. spiculum, a point). Pointed needle-shaped bodies. 

 Spirifera (Lat. spira, a spire or coil ; fero, I carry). An extinct genus of 



Brachiopods, with large spiral supports for .the "arms." 

 Spirorbis (Lat. spira, a spire ; orbis, a circle). A genus of tube-inhabiting 



Annelides, in which the shelly tube is coiled into a spiral disc. 

 Spongida (Gr, spoggos, a sponge). The division of Protozoa commonly known 



as sponges. 

 Stalactites (Gr. stalasso, 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, stromxx, a thing spread out ; pores, a passage or pore). A 



Palseozoic genus of Protozoa. 

 Strophomena (Gr. strophao, I twist ; mene, moon). An extinct genus of 



Brachiopods. 

 Sub-calcareous, Somewhat calcareous. 

 Sub-central. Nearly central, but not quite. 



Suture (Lat. sua, I sew). The line of junction of two parts which are immov- 

 ably connected together. Applied to the line where the whorls of a univalve 



shell join one another ; also to the lines made upon the exterior of the shell 



of a chambered Cephalopod by the margins of the septa. 

 Syringopora (Gr. surigx, a pipe ; pores, a pore). A genus of Tabulate Corals. 



Tabula (Lat. tabula, a tablet). Horizontal plates or floors found in some 

 Corals, extending across the cavity of the " theca " from side to side. 



Tegumentart (Lat. tegumentum, a covering). Connected with the integu- 

 ment or skin. 



Teleosaurus (Gr. ieleios, perfect ; saura, lizard). An extinct genus of Cro- 

 codilian Reptiles. 



Teleostei {Gv. teleios, perfect; osteon, bone). The order of the "Bony 

 Fishes," 



