0» cellule sa -43- 
Prom the Conglomerate of Antigua* Coll* Geol. Soc. 
Dimensions * — -Height of eorallum several inches • Diameter 
of corallites from 1-2 lines.” 
H The minute details of the structure of this Coral have 
disappeared; hut the brilliant porcellanous silica which fills up 
the intersept al loculi and the exothecal cells is so easily 
distinguished from the dull colourless remains of the septa, 
dissepiments , and walls, that the characters described are ea,sily 
seen in the specimens. In some parts of the specimens the 
sclerenchyma is whitish grey, and the interspaces are filled with 
dark homogeneous silica, just reversing the arrangement generally 
observed. 
The intimate relation between this form and one from a later 
formation (the Chert) is very interesting* The latter (var, 
curvata) has the teeth on the septa preserved; and the septa of 
the third order curve towards those of the second near the 
columella. It has all the other structural peculiarities of the 
