PLATE IX. 



Hemipedinas from the Lias. 



Fig. 



1 a. Hemipedina Bechei, Brodrijj, p. 144. Test with spines in situ, natural size. 

 b. A primary spine, magnified three times. 



2 a. Hemipedina Bowerbankii, Wright,^. 145. Test with spines, natural size. 



b. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous 



zones ; magnified five diameters, 



c. A primary spine, magnified three times. 



3 a. Hemipedina (Diadema) Serials, Leymerie, p. 146. From the Lias of France 



copied from the '^Mem. de la Societe Geologique de France,' t. ii, pi. 24, fig. 1. 

 To show the form and structure of the test of a very rare allied species. 

 b. One of the inter-ambulacral plates and poriferous zones, magnified. 



4 a. Hemipedina Jardinii, Wright, p. 146. Upper surface of the test, natural size. 



b. Under surface of the test, natural size. 



c. Lateral view of the test, natural size. 



d. Upper surface of the test, magnified three diameters. 



e. Under surface of the test, magnified three diameters. 

 /. Lateral view of the test, magnified three diameters. 



g. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous 

 zones, magnified nine times. 



5 a. Hemipedina Etheridgii, ^n^^^f, p. 148. Upper surface of the test, natural size. 

 h. Under surface of the test, natural size. 



c. Lateral view of the test, natural size. 



d. Upper surface of the test, magnified three diameters. 



e. Under surface of the test, magnified three diameters. 

 /. Lateral view of the test, magnified three diameters. 



g. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous 

 zones, magnified nine times. 



