Figure la. Upper surface of the test. 



lb. Lower surface of the test. 



lc. Lateral surface of the test. 



Id. Apical system, X 5. 



le. Ambulacrum, X 3. 



If. Portion of ambulacrum, X 8. 



lg. Interambulacrum, X 3. 



lh. Portion of interambulacrum, X 8. 

 252 



PLATE XXIII. 



Pedinopsis symmetrica (Cragin) (p. 64). 

 Geol. Survey Texas, type. 



