M 
Genus Hicksonia. 
In 1886 Professor S. J. Hickson published a preliminary account of Clavularia viridis 
Ouoy et Gaimard from Celebes, and pointed out the presence of remarkable tubes connecting 
the polyps, and the similarity of the expanded polyps, both in form and colour, to those of 
Tubipora. In 1894 he published a description of the interesting form and gave a beautiful 
drawing of the colony. 
In 1906 Professor W. Kuicenthal referred Clavularia viridis Ouoy et Gaimard to the 
genus Anthelia which he distinguished from Clavularia because its polyps do not show any division 
into a calycine and a retractile portion. Whether the species described by Ouoy and Gaimard 
was an Anthelia or not, there is no question that the form referred by Hickson to Claviilaria 
viridis has a very marked calyx into which an anthocodial region can be retracted. 
In 1901 Delage and H^rouard established a new genus Hicksonia for the form described 
by Hickson as Claviilaria viridis Ouoy et Gaimard on account of the connecting tubes which 
extend from polyp to polyp. They also emphasised the thickness of the mesogloea and the dense 
system of “horny” fibres. It is difficult to determine the exact nature of this horny skeleton but 
it is apparently closely related to Keratin (Hickson, 1894). A mistake, however, was made in 
stating that the upper part of the polyp is without spicules, for these are abundant in specimens 
which Professor Hickson was good enough to identify with those he originally described. 
Here we propose (1) to add a few details to Professor Hickson’s description of Clavu¬ 
laria viridis , (2) to describe a distinctly new species ( Hicksonia kollikeri Dean), and (3) to call 
attention to two interesting points regarding spiculation, namely (a), the occurrence of interlocked 
Telestid-like, almost antlered, forms which suggest the derivation of Telestids from Clavularids, 
and (<$), the extraordinary variability in the details of the large warty spindles in what we feel 
compelled to regard as a single species (. Hicksonia kollikeri). 
1. Hicksonia viridis (Ouoy et Gaimard). (Plate XII, Figs. 7 and 8). 
Stat. 131. Karakelang Islands. 1 Ex. 
Stat. 213. Saleyer. Reef. 2 Ex. Large, broken up colonies. 
Specimens of this interesting type obtained in the Siboga Expedition, from Saleyer Reef, 
and Karakelang Island (no depth is recorded) agree closely with Professor Hickson's description 
in 1894 of Clavularia viridis Ouoy and Gaimard. The general appearance and mode of growth 
of the colony is almost identical. The connecting stolons with average lengths of 2 to 3 mm. 
appear, however, to be rather shorter than those of the 1894 specimen; the whole colony seems 
to be more compact. The finest colony from Saleyer has a height of 7.5 cm. and diameters 
of 11.5 and 5.3 cm. The longest polyp had a length of 5.4 cm. and an average diameter of 3 mm. 
The retractile portion of the polyps is leathery in texture, creamy white in colour, and 
differs from that of Professor Hickson’s C. viridis in being dusted with innumerable very minute 
oblong, oval, or disc-like spicules, which are all divided into 2, 4, or several sectors by lines 
radiating from a central point. Average dimensions of the spicules are 0.03 X 0.03 nun. ; 
0.03 X 0.02 mm. 
