PLATE LIII. 



Linthia tumidula Clark (p. 99). 



Am. Mus. Nat. Hist., type. 

 Figure la. Upper surface of the test, 

 lb. Lower surface of the test, 

 lc. Lateral surface of the test. 

 Id. Posterior surface of the test, 

 le. Upper portion of the anterior ambulacrum, X 5. 



If. Several plates from the petaloidal region of the left posterolateral ambulacrum, X 

 lg. Apical system, X 5. 

 lh. Tubercle from the side, X 20. 

 li. Tubercle from above, X 20. 



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