NIAGARA FALLS AND VICINITY 273 



saddles — forward bending portions of the suture in the shells of cephalopods 



salient — standing out prominently 



scabrous — rough or harsh with little projecting points 



scalae — small transverse plates in the genus Unitrypa of the bryozoa 



scalariform — stair or ladder-shaped 



sclerenchyma — calcareous tissue deposited by the coral polyps 



scorpioid — scorpion-like, coiled like the tail of a scorpion 



semilunar — crescentic, or resembling a half moon 



semiovate — half egg-shaped 



senile— pertaining to old age 



septal radii — radiating ridges taking the place of septa in certain corals 



septate — with partitions or septa 



septum — partition; in corals, the radiating calcareous plates; in cephalopods, 



the transverse partitions between the chambers 

 serrate — notched like a saw 

 setiferous — bristle-bearing 



sigmoid — curved like the Greek letter I (signia) 

 sinistral — left handed, reversed coiling of some gastropod shells 

 sinuate — wavy, winding 



sinuosity — notch or incision forming a wavy outline 

 sinus — impression in the surface or margin of a shell 



siphonal funnel — siphonal projection from the septum of a cephalopod shell 

 siphonal lobe — lobe in the suture of an ammonoid shell, corresponding in 



position to the siphuncle 

 siphuncle — tubular canal passing through the air chambers in the shells of 



cephalopods 

 slickensides — polished or striated surfaces on rock due to motion under 



great pressure 

 sockets — hollows in the brachial valve of brachiopods for the reception of 



the teeth of the opposite valve 

 spatulate — shaped like a spatula; spoon-shaped 

 spheroidal — globose, of the form of a spheroid 

 spiniform — spine-like 

 spinulose — spine bearing 



spondylium — spoon-shaped cavity under the beak of pentameroid brachio- 

 pods 

 squamous — scaly, covered with scales 

 stalk — stem of crinoids 



stellate — star-shaped; arranged in star-like manner 

 stipe — stalk or stem in plants 

 stock — main stem or trunk 

 striae — fine radiating surface lines of shells 

 stylolites — peculiar columnar and striated rock form seen in limestones at 



the junction of two layers 

 sub — in composition indicates a low degree: sub-angular — rather angular; 



sub-carinate — somewhat toothed, etc. 



