TAB. I. 



CORALS FROM THE CRAG. 



Sphenotrochus intermedius (p. 2). 



Fig. 1 . An adult specimen ; natural size. 



1 a. An adult specimen ; variety having a dilated basis ; natural size. 



1 b. A magnified view of the specimen represented at fig. 1. 



1 c. A vertical section of the same, corresponding to the short diameter of the 



calice ; magnified. 

 1 d. Calice of the same ; magnified. 



1 e. A very young individual, magnified j the natural size is indicated by the 



length of the line placed near this figure. 

 if, 1 g, 1 h, 1 i. A series of young individuals, at different periods of their growth ; 

 magnified. 



Flabellum Woodii (p. 6). 



Fig. 2. A side view of the corallum ; natural size. 



2 a. A specimen magnified, and showing the mode of arrangement of the septa ; 



one half of the calice has been cut away down to the bottom of the fossula. 



2 b. Calice entire ; natural size. 



Balakophyllia calycultts (p. 9). 



Fig. 3. Two individuals cemented together by their basis ; natural size. 



3 a. A variety with a narrow basis ; natural size. 



3 b. An individual remarkably tall, with its calicular extremity worn away ; natural 



size. 

 3 c. Horizontal section of the same, near the calice, magnified so as to show the 



mode of arrangement of the septa. 



3 d. A fragment of the wall deprived of its epitheca, and much magnified. 



Cryptangia Woodii (p. 7). 



Fig. 4. A small aggregation of corallites imbedded in a mass of Cellepora; natural 

 size. 



4 a. One of these corallites extracted from the mass of Cellepora, and showing its 



epitheca ; natural size. 

 4 b. One of the same separated from the extraneous mass, and having its epitheca 



dimpled by pressure of the surrounding Cellepora. 

 4 c. Calice, magnified. 

 4 d. One of the same corallites magnified, and having part of its calice cut away 



so as to show the denticulate edge of the septa ; the dimples of the epitheca 



are accidental and produced by the investing Cellepora. 



