MUSEUM OF COMPARATIVE ZOOLOGY. 63 



EXPLANATION OF THE PLATES. 



PLATE I. 



Orbicella annularis Dana (natural size). 

 The thickness of the coral at the edge of the mass varies from f to f of an inch. 

 The greatest height of the mass above the cable is 2^ inches. 



PLATE II. 



Orbicella annularis Dana (natural size). 



The thickness of this specimen is very much less than that of Plate I. It varies 

 at the edge of the mass from | to ^ of an inch. The greatest height above 

 the cable is 2\ inches. 



PLATE III. 



Mamcina areolata, Ehrenb , 



1. Seen in profile. The thickness above the cable is one inch. 



2. Same, seen from above. 



Both figures natural size. 



PLATE IV. 



Isophyllia dipsacea Ag. (natural size) 

 The greatest thickness is 2| inches 



