PLATE X. 



Hemipedinas from the Inferior Oolite. 



Fig. 



1 a. Hemipedina Bakeri, Wright, p. 149. Under surface of the test, natural size. 



b. Upper surface of the test, magnified two diameters, 



c. Lateral view of the test, magnified two diameters, 



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



rows ; magnified two diameters. 



e. Inter-ambulacral plate and tubercle, seen in profile, and magnified three times. 

 /. The apical disc, magnified three diameters. 



2 a. Hemipedina PEREORATA, Wright, p. 151. Lateral view of a test, natural size. 

 b. Upper surface, magnified two diameters. 



e. Under surface, magnified two diameters, 



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



rows ; magnified six times. 



e. Apical disc, magnified two diameters. 



/. Base of an ambulacral area, showing the trigeminal arrangement of the poriferous 

 zones in this region. 



3 a. Hemipedina TETRAGRAMMA, Wright, p. 152. Lateral view of the test, natural size. 



b. The upper surface, magnified two diameters. 



c. Two inter-ambulacral plates, and a portion of an ambulacral area, with the poriferous 



zones ; magnified five diameters. 



4 a. Hemipedina Waterhousei, Wright, p. 154. Lateral view of the test, natural size. 



b. Upper surface, magnified two diameters. 



c. Lateral view, magnified two diameters. 



d. Apical disc, magnified four diameters. 



e. Two inter-ambulacral plates, and a portion of an ambulacral area, with the poriferous 



zones ; magnified three diameters. 



5 a. Hemipedina Bonei, Wright, p. 156. Lateral view of the test, natural size. 



b. Upper surface of the test, magnified two diameters. 



c. Under surface of the test, magnified two diameters. 



d. Three inter-ambulacral plates, and a portion of an ambulacral area, with the poriferous 



zones ; magnified six diameters. 



