.".78 



Septum— a partition; in corals, the radiating calcareous 



plates; in Cephalopoda, the transverse partition between 

 the chambers. 

 Setiferous — bristle-bearing. 



Sin-moid — curved like the Greek letter s (sigma). 



Sinuate — wavy, winding. 



Sinus— an impression in the surface or margin of a shell. 



Siphonal funnel — the siphonal projection from the septum 

 of a Cephalopod shell. 



Siphonal lobe — the lobe, in the suture of an Ammonoid shell, 

 corresponding in position to the siphuncle. 



Siphuncle — the tubular canal, passing through the air- 

 chambers in the shells of Cephalopods. 



Spatulate — shaped like a spatula; spoon-shaped. 



Spinulose — spine bearing. 



Sub — in composition indicates a low degree: sub-angular — 

 rather angular; sub-carinate — somewhat toothed, etc. 



Sulcus — a furrow. 



Suture — in Cephalopods — the line of juncture between shell 

 and septum, seen on breaking away the former; in 

 Gastropods — the external line of juncture between the 

 several whorls: in Trilobites — the dividing line between 

 fixed and free cheeks, commonlv called facial suture ; 

 in Crinoids — the line of juncture between adjacent 

 plates. 



Tabulae — the transverse, continuous partitions or floors in 



corals, etc. 

 Tegmen — the vault or cover of the calyx in Crinoids. 

 Terebratuloid—\\ke the recent genus Terebratula. 

 Test— shell. 



Tetrameral — on the plan of four. 

 Theca — the proper wall of the individual corals. 

 Thorax— the central part of the body of the Trilobites. 

 Trabecules — ] trojecting bars. 

 Trigonal— three-angled . 

 Trihedral — with three equal faces. 



