PLATE XL 



Hemipedinas from the Coral Bag. 



Fig. 



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



b. 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. 



2 a. Hemipedina tuberculosa, Wright, p. 1 64. Upper surface of the test, natural 



size. 



b. 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 situ, on a slab of Great 



Oolite from Stratton, near Cirencester. 

 b. A primary spine, magnified three times. 

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



