PLATE VI. 



C1DARI8 CALiFORNicus Clark (page 36). 



Fig. la. Spine, enlarged. 

 Ife. Ditto. 

 Ic. Articular surface of lb, much enlarged. 



CiDARis TAYLORENSis Clark (page 35). 



Fig. 2a. Fragment of two contiguous interambulacral plates of the same series. 

 2b. Spine. 



CiDAKis 8PLBNDEN8 Morton (page 33). 



Fig. 3a. Portion of test, natural size. 



3b, Interambulacral plate, magnified two diameters. 

 3c, Ambulacral area, highly magnified. 

 3d. Tubercle, enlarged. 



3e. Spine. , 



^ 3/. Base of same much enlarged. 

 3g. Articular surface of spine. 



CiDARis Walcotti Clark (page 37), 



Fig, 4a, Portion of test, natural siz-e. 



ib. Interambulacral plates, enlarged. 

 4c. Ambulacral area, highly magnified, 

 id. Tubercle, enlarged, 



11§ 



