PLATE XI''. 



Echinaiithus rosaceus. 



1. Seen from ;il)o\i', showing ramifications of water system. 



2. S;uiie from actinal side. 



3. Another specimen, in wliicli the actinal floor has been removed to show pillars and isolation of ambu- 



lacra from the main cavity. 



4. Another specimen-, showing teeth in situ, and the pores forming communication between the double 



floor and the maiu cavity. 



(^All Jigs, ^ natural size.) 



