
AGGREGATED COLONIES IN MADREPORARIAN 
CORALS. 
J. E. DUERDEN. 
ProF. G. von Kocu,! in the eighth of his well-known 
« Kleinere Mittheilungen über Anthozoen," describes what 
he terms * Aggregated Colonies” as occurring in the simple 
Mediterranean coral, Balanophyllia verrucaria. The designa- 
tion *aggregated" is employed by the author for such colonies 
as have been formed through the secondary fusion of individ- 
uals which were originally distinct, thus distinguishing them 
from most other Anthozoan colonies which are produced by 
the budding or fission of a single individual. 
Von Koch collected around the small island of Vivara in the 
Mediterranean Sea a number of Balanophyllia which, instead of 
retaining the simple habit usual for this genus, consisted of two 
or more polyps. The corallites were fused with one another 
and possessed a common base, and many of the septa of adja- 
cent calices were continuous. The tentacular system of each 
individual polyp was distinct, a mouth occurred in the center 
of each oral disk, but the column wall passed uninterruptedly 
from one polyp to another. DUM : 
An examination of serial transverse sections of the corallum 
of two such colonies revealed that the corallites were inde- 
pendent towards the base, but united in a common secondary 
skeletal formation. In the case of a colony constituted of two 
individuals, one much larger than the other, von Koch con- 
cludes that the union had arisen through a larva settling near 
an older polyp; after the first skeletal rudiments were formed 
their coralla became fused through secondary deposition of 
calcareous matter, the larger polyp contributing most. 
1 Koch, G. von. Kleinere Mittheilungen über Anthozoen. VIII. Aggregirte 
Kolonien von Balanophyllia verrucaria Aut. Morph. Jahrb., vol. xviii. 
461 : 
