586 
G. HERBERT FOWLER. 
pedicle, each corresponding exactly in position with a septum. 
These do not agree with von Koch's views as to the origin of the 
theca from fusion of the septa ; to accord with which costae 
should be developed in this position, such as occur in many 
forms. 
The whole of the exterior surface of the theca shows well- 
marked lines of growth (tig. 4), so arranged as to appear to 
indicate that the chief centres of activity for the secretion of 
coral lie in the septa. Hence the lip of the calyx is slightly 
dentate (figs. 3, 4). 
While the upper fourth of the external surface of the theca is, 
like the whole of the interior of the calyx, glistening, white and 
hard, the lower three fourths are soft in texture and brownish. 
This latter portion was described by Moseley as a “ light-brown 
epitheca.” But on decalcification the brown substance falls off 
as soft flakes, which, by means of sections, are found to consist 
of dead tissues and algal (?) parasites. There is really no 
epitheca present, recognisable as such in the adult. 
The columella (fig. 3, col.) is incomplete, the septa not 
always meeting regularly along their free edges. 
In the retracted condition of the polyp there is no tissue 
external to the corallum (figs. 1, 2), nothing corresponding to 
the condition described by Heider in Cladocora and by Koch 
in Caryophyllia. When expanded, however, the soft tissues 
almost certainly stretch outwards and downwards over the 
upper fourth of the exterior of the theca, which is thus kept 
white and hard, as mentioned above. Were the polyp thus 
completely expanded to be plunged into a killing fluid, the 
same appearances would ensue as the above-named observers 
have described. 
ii. Anatomy. — This agrees in all essential details with the 
Actmian type, except in the absence of an external body wall, 
the whole polyp being enclosed in the corallum (figs. 1, 2). 
Moseley mentions that in some specimens tissues external to 
the theca were observed round the lip, and figures them ( 11 ), 
pi. xvi, fig. 10, as consisting of ectoderm and mesoderm, but 
had not the means of studying them by sections. None of my 
