18 G. LINDSTRÖM, ACTINOLOGY OF THE ATL. OCEAN. 
disappear in calicles which have attained a few millimeters in length and their place 
is left empty. Thence the septal formula in small specimens is (two systems taken): 
OMETDN Slap FOO FAST NA FAS RANN 
and in adult specimens: 
PUST PRE OmpRag TIP RUNNER 
The interior margin of the septa of the third order is very closely serrated by minute 
teeth. The partitions between this septum and the neighbouring ones are distinctly 
marked on the outside of the coral. They are narrow at the base of the coral, where 
the septum is largest, and diverge from each other the higher they reach and the 
smaller the septum grows. When the epitheca is peeled off, there are formed narrow 
longitudinal slits, and when nothing else holds the septum attached to the nearest sep- 
tum the coral is ready to split or to break up in segments, a catastrophe in the life 
of the polyp, no doubt much accelerated by the increase of bulk of the animal itself, 
in consequence of which the loosely coherent segments of its coral are pushed apart. When 
this happens the coral may be severed in twelve quite independent segments, viz. the six septa 
of the third order detached from their feeble hold between the secondary ones, and again 
six segments formed by the primary septa and their enclosing secondary ones, forming 
almost a compact mass, being as above described connected by the lateral processes 
in the locula. When this dissevering of the component segments of the coral hap- 
pened, it is evident that the animal remained attached to one or more of these frag- 
ments and began to form a new caliele around itself and this grows up anew, the 
fragments of the old caliele firmly attached to it (P1. III, figs 30 & 31). I think it 
is rather a continuation of the same individual, growing from the fragments left, than 
a gemmation of a new individual from a parent, the calicle of which it breaks up. 
There are many instances evidently indicating that the calicle thus formed on the top 
of a split coral as to a moiety consists of a new formed wall and new septa (P1. III, 
fig. 33). The new calicle in this instance encloses two old systems and four new ones. 
All the old septa are in uninterrupted continuation, the new ones only a little more 
narrow and shorter than the older. Moreover there are specimens having the new 
calicles attached to two or even three segments of the old coral, widely apart from 
each other as shown in figure 30. This seems to point out the suddenness with which 
the cleaving of the coral took place, and that the animal still clung to the wrecks of 
its old coral, and was able to keep them together while it formed a new calicle. 
If there had been a small bud inside the caliele, it could not have been able to em- 
brace and attach to itself two dissevered segments and less so three. It is, however, 
very difficult to draw a line of distinction between such an interruption of growth in 
the same individual and an intracalicinal gemmation. It may be, that these two changes 
in the life process of the coral sometimes merge into each other. In several Palwozoic 
genera as Acervularia, Ptychophyllum and also in some recent ones, there is a row 
of buds inside the calicle, and these embrace within their new caliecle one or two septa 
of the parent coral, so that this young calicle encloses partly old septa, partly new 
ones. But quite the same thing happens also when the polyp is decreasing in volume 
and is forming a partially new caliele inside the old, using one segment of its old 
2 ———tOA— —- 
