1886. ] MADREPURARIAN CORAL. 135 
that all the hard parts of the coral are laid down by these cells, 
which can be always found between the mesodermal lamella and 
the hard parts. Koch (9) showed that the calycoblasts were really 
the remains of the basal ectoderm-cells of the embryo, so that the 
whole of the corallum is laid down by ectoderm, and is really, mor- 
phologically, outside the coral. This of course corrects the old view 
which regarded the basal ectoderm of a coral as having disappeared 
from the outside of the corallum, since what remains of the basal 
ectoderm is really within the corallum, and is the very means of 
forming the corallum. Koch (9, plate xx. fig. 9) gives a repre- 
sentation of three calycoblastic cells, which seem to be merely ordinary 
high epithelial cells, nucleated and filled with granules. 
I have found everywhere between the corallum and the mesoderm 
lamella a tissue or series of cells, represented in Plate XIV. figs. 10-13, 
cal. ; these I believe to be the calycoblasts described by Heider and 
Koch. That these cells must be calycoblasts is, I think, evident 
from their position, since they are everywhere found between the 
corallum and the mesoderm lamella. But in form they are very 
different from the calycoblasts figured by Koch, for, whereas Koch’s 
calycoblasts are, as was said above, ordinary granulated epidermic 
cells, the cells which I have found in Stephanotrochus are not 
quadrangular but of irregular shape, and separated from one another 
by intervals, so that they seldom form a definite layer; also they are 
striated in a most extraordinary way, as is shown in figure 12. 
Whether these cells are the calycoblasts of Koch I cannot with 
certainty say; it may be that the difference of appearance is due to 
the fact that Koch’s figure represents these cells in a very young state, 
when they are doubtless more active than in the adult coral; or, 
again, the calycoblasts of Koch’s form <Asteroides may differ essen- 
tially from those of Stephanotrochus. The fact is, however, that 
until more is known of the anatomy of other corals, it is impossible 
to decide on the nature of these cells. 
In conclusion I must thank Prof. Moseley for kindly allowing me 
to examine this coral, also for his advice and assistance; so, too, I 
must record my obligations to Prof. Ray Lankester, and my friend 
Mr. Fowler, for much help. 
I append a list of the principal publications referred to; I have 
abstained from quoting the views and discoveries of the last few 
years with regard to Madreporarian corals, since a very complete 
history of recent researches on the subject will be found in Mr. 
Fowler’s paper (4). 
VI. List of Publications on the subject. 
1. Moserey, H.N. Report on certain Hydroid, Alcyonarian, and 
Madreporarian Corals, procured during the voyage of H.M.S. 
‘Challenger. —Report of the Voyage of H.M.S. ‘Challenger,’ 
Zoology, vol.ii. 1881. (Description of Stephanotrochus, p. 151.) 
2. Tizarp and Murray. Exploration of the Farée Channel during 
the summer of 1880 in H.M’s hired ship ‘ Knight Errant.’— 
Proc. Royal Soc. Edinburgh, no. 111. p. 638. 
3. Martin Duncan, P. A Revision of the Families and Genera of 
