St < 



Post-palmars — all the plates superior to the axillary pal- 

 mars in the arms of Crinoids. 



Proliferous — reproducing buds from the calyx. 



Protoconch — the embryonic shell of acephalous molluscan. 



Pseudo-columella — false columella in corals, formed by a 

 twisting of the septa. 



Pseudo-deltidium — false deltidium ( Spirifer), formed 1 »y union 

 of the two deltidial plates. 



Pseudo-septa — septa-like ridges of Cluetedes, etc.; the 

 projecting ends of the lunaria in the cells of certain 

 Bryozoa. 



Pustulose — bearing pustules or projections. 



Pygidium — the posterior or tail-portion of the carapace of 

 Trilobites. 



Pyriform — pear-shaped. 



Quadrifid — cut into four points. 

 Quadrilobate — bearing four lobes. 



Raehis — the central stem of a frond in Bryozoa. etc. 

 Radials— the main plates of the calyx of a Crinoid, resting 



on the para-basals, and alternating with them. 

 Radii— the ribs or striations diverging from the beak of a 



shell. 

 Ramose — branching. 

 Reticulated — like a network. 

 Retral — backward. 



Rhynchonelloid — resembling Rhynchonella. 

 Rugosa — m\ old name for the Tetracoralla. 



Saddles— the forward bending portions of the suture in the 



shells of Cephalopods. 

 Scalse— small transverse plates in the genus Unitrypa of the 



Bryozoa (which see). 

 Sealariform — stair or ladder-shaped. 

 Sclerenchym a— the calcareous tissue deposited by the coral 



polyps. 



