PLATE VI. 



LAOTIRA CAMBRIA (p. 32). 



Fig. 1. View of a somewhat flattened exumbrella. 



Fig. la. Subumbrella view of fig. 1, showing the exumbrella lobes slightly twisted. 



Fig. lb. Lateral view of figs. 1, la, showing convexity of the subumbrella and its lobes. 



Fig. 2, 2a, 2b. Upper, lower, and side view of an individual in which the subumbrella is flattened 



and the exumbrella is strongly convexed. This is in direct contrast with figs. 1, la, lb. 

 Fig. 3. The subumbrella side of a T-lobed individual in which the lobes are almost entirely concealed 



by the deposit of siliceous matter about them. 

 Figs. 4, la. Upper and lower view of a specimen in which the exumbrella and subumbrella corre- 

 spond very closely. 

 Fig. 5. View of the subumbrella of a small, somewhat worn specimen showing 9 lobes and 1 interra- 



dial lobe or arm (a;) . 

 Fk;. 5a. Exumbrella view of fig. 5, showing 7 lobes, two of the lobes shown in fig. 5 not appearing 



on the upper surface, excepting one which appears as little more than a line at x. 

 Fig. 6. A somewhat common form in the collections, which has very narrow lobes that have been 



more or less concealed by a deposit of siliceous matter. 

 Figs. 7, 7a. Exumbrella and subumbrella surfaces of a somewhat compressed specimen. 

 Fig. 7b. Side view of fig. 7, in which the specimen appears to be resting on the exumbrella surface, 



but, owing to the deposit of siliceous matter, it is not possible to say which is the upper 



or lower side. 

 Fig. 8. Exumbrella of a specimen having 8 rather wide lobes. This may be compared with fig. 1 of 



PI. I. 



116 



