1909 TERMINOLOGY ix 



Ornament : — 



Radius — a stria (line) or casta (rib), or combination 

 thereof, character and direction indicated thus : — 



recti- 



fiexi- 



prorsi- 



versi- 



rursi- 



anguli- 



straight I character, 



curved ) 



radius inchned >. 



radially projected I general 

 reclined | trend. 



V-shaped -^ 



Tubercle — ^general term for knob, pimple, or any spine- 

 like projection, sub-divided thus : — 



spine a strong projection. 



nodtis a round knob. 



papilla a pimple. 



bulla a knob transversely elongate. 



clavus a knob longitudinally elongate. 



auriculoid an ear-like or c; -shaped marking, 



produced by the degeneration of 

 a clavus : see below, p. x. 



Partitions 



Septal margin — ^the suture line, or edge of partition between 

 chambers. The following abbreviations for parts will 

 be used : — * 



Lobes : — 



EL. on venter (external). 



L^ principal lateral. 



Z,* second lateral. 



L* third lateral, often first of a series 



of auxiliaries. 

 IL on dorsum (internal). 



Aux. ^, '^: auxiliaries. 

 Ac '■ ^- accessory lobes developed between 



EL and L. 



Saddles : — 



ES external (between EL and L^). 



SI 1st lateral (between L^ and L^). 



S* 2nd lateral (between L^ and L^). 



The Septal margin (suture line) is often called the septum ; but 

 there are other septa, for instance ; — 



Septicarina a carina ^ with a 



Septicosta a rib > septum 



Septituberculus a tubercle J at base. 



I See also Hyatt, Eastman trans. Zittel, Pal. I, 539, 1900. 



