PLATE LXII. 



Periarchus lyelli Conrad (p. 131). 

 Johns Hopkins Univ. T 2003, specimen B. 



Figure la. Upper surface of the test, 

 lb. Lower surface of the test, 

 lc. Lateral surface of the test. 



Periarchus lyelli Conrad (p. 131). 

 Johns Hopkins Univ. T 2004, specimen C. 



Figure 2a. Upper surface of the test. 

 2b. Lower surface of the test. 

 2c. Lateral surface of the test. 

 2d. Posterior surface of the test. 



Periarchus protuberans Twitchell, n. sp. (p. 133). 



U. S. Nat. Mus. 164685, type. 



Figure 3a. Upper surface of the test. 



3b. Lower surface of the test. 



3c. Lateral surface of the test. 



3d . Posterior surface of the test. 



3e. Part of one ambulacrum, X 8. 



3f. Apical system, X 8. 



