308 MR. S. PACE ON THE 
On the Corallum of Turbinaria. By 8. Pacr, F.Z.S. (Com- 
municated by H. M. Brernarp, M.A., F.L.S.) 
[Read 18th April, 1901.] 
The Formation of the Cup. 
No actual observations upon the early stages in the growth of 
the remarkable cup-shaped corallum of Turbinaria appear to 
have been yet recorded. It has usually been assumed that the 
parent polyp becomes submerged in the common ccenenchyma of 
the coral, and that its calicle is not recognizable after the 
corallum has attained the cup form. Thus Mr. H. M. Bernard, 
an admitted authority on this group, writes *:—“ A ring of buds 
shoots up round and from the sides of the parent polyp, together 
forming a cup, the wall of each bud rising up as a distinct cone 
above the level of the fusion of their walls to form the common 
ceenenchyma. The parent polyp dies away, and its primitive 
protuberant cone is immersed under the conenchyma formed 
from the fusion of the walls of a ring of daughters. These 
daughters carry on the colony, the budding of the daughters 
being limited to their free or outer sides, z. e. to the sides 
turned away from the axis of the cup.” To illustrate his com- 
parison with what occurs in the case of Madrepora, Mr. Bernard 
gives the two diagramst which are copied in figs. 1&2. The 
supposed dying away of the parent polyp in Turbinaria was 
evidently assumed in order to explain the fact that it is so very 
unusual to find any trace of a calicle occupying a central 
position at the base of the cup. 
An examination of younger growth-stagest than are con- 
tamed in the British Museum collection, and the dissection of 
several small cups, have revealed the interesting fact that the 
parent polyp does not die away, but that it bends over to one 
side and takes part with its daughters in forming the rim of the 
cup. In a normal cup the parent calicle can always be traced 
as one, generally the largest, of the innermost ring of calicles. 
* Ann. Nat. Hist., ser. 6, vol. xx. (1897), pp. 131-2. 
+ Catal. Madrep. Corals Brit. Mus., vol. ii. London, 1896. 
+ The corals collected by me in Torres Straits I have presented to the 
British Museum. 
