PLATE LXXX. 



Fig. 1. PsEUDODiADEMA FRAGILE, Wiltshire. Exterior surface of an interambulacral 



plate, magnified eight diameters. 



2. — — — Under surface of test, somewhat crushed 



and broken, natural size. 



3. — — — Spine, natural size. 



4. — — — Portion of surface of spine, magnified 



sixteen diameters. 



5. — — — Interior surface of a plate, magnified 



four diameters. 



6. — — — Under surface plates of ambulacral and 



interambulacral areas, magnified four 

 diameters. 



7. — — — Upper surface of test, natural size. 



8. — — — Spine, magnified eight diameters. 



9. — — — Section of interambulacral plate (Fig. 1), 



passing through the primary tubercle. 

 10. — — — Transverse section of spine (Fig. 3), 



magnified twenty diameters. 



The specimens figured are from the collection of the Rev. Prof. Thos. Wiltshire, F.G.S. 



