0. crassolamsllata -28- 
all the corallitea being badly developed, except those with four 
cycles; and the expression of its septal number must he three 
cycles, the third being occasionally wanting in some systems, and 
four cycles being the extreme range. The variability in the 
septal number is very character! stic of this variety. The oxo- 
thecal dissepiments are abundant, and bifurcate here and there. 
Marl- format ion of Antigua. Coll* Geol. Soc 
