PLATE X. 



Salenia texana Credner (page 40). 



Fig. la. Upper surface of the test, natural size. 

 Ih. Under surface of the same. 

 If. Lateral surface of the same. 

 Id. Interambulacral area, magnified two diameters. 

 le. Ambulacral area, magnified three diameters. 

 1/. Portion of the same, highly magnified. 

 Ig. Apical disk, enlarged. 

 Ih. Tubercle, enlarged. 

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