Smithsonian Report, 1961.— Whittington 



Plate 4 



1. Enrolled exoskeleton of Ordovlcian genus Flexicalymene is seen from the side. Cup- 

 shaped structure at top is eye, with suture line running to side. X3.5. 



2. From front, Flexicalymene shows the three-lobed form that prompted the name 

 "Trilobita" for these animals. The shell splits on suture line at molting, X3.5. 



