PLATE XL 



Hemipedinas from the Coral Mag. 



Fig. 



1 a. Hemipedina Marchamensis, WrigU, p. 161. Base of the test, natural size. 



h. One inter-ambulacral plate, a portion of the ambulacral area, and poriferous zones, 

 magnified twice. 



c. Lateral view of a primary tubercle, showing its prominent boss, with smooth summit. 



'la. Hemipedina tuberculosa, WrigU, p. 164. Upper surface of the test, natural 

 size. 

 h. Base of the test, natural size. 



c. Lateral view of the test, natural size. 



d. Two inter-ambulacral plates, a portion of the ambulacral area, and poriferous zones, 



magnified three times. 



e. Lateral view of a primary tubercle, showing the prominent boss, with its smooth 



summit, and the scrobicular granules encircling the areola. 

 /. A primary spine, magnified three times. 



Hemicidaris from the Great Oolite. 



3 a. Hemicidaris Bravenderi, Wright, p. 84. Test and spines in ^^Y?*!, on a slab of Great 

 Oolite from Stratton, near Cirencester. 

 h. A primary spine, magnified three times, 

 c- Base of a spine, showing the crenulated rim of its acetabulum and the milled ring. 



