0. megalaxona -47' 
cate, a little thicker at the wall than elsewhere, and very thin 
towards the columella* in six systems, the cycles varying greatly; 
thus, in many corallites there are two cycles, in others two 
cycles and a third in one or more systems. Three perfect cycles 
are seen in large corallites, and two additional septa in some 
(in the whole corallite). The primary septa have a tooth near 
the wall; the secondary are a little smaller than the primary. 
Columella lax, parietal, occupying a very large space. 
The details can he made out in only one corallite, which 
has escaped the ruinous hut remarkable f ossilization that has 
destroyed them in most of the specimens. The details have 
nearly all disappeared in the mass, and the intersept al loculi 
look like blunt, thick septa. In some specimens the large space 
occupied by the columella is filled with silica of a white or of 
a black color, giving them a very curious appearance. 
There are many corallites which appear to have been under- 
going fissiparous growth, but it is evident that extra-calicular 
gemmation also occurred. There are few details left for a 
