V 
194 
REMARKS ON SYSTEMATIC POSITION 
Before entering into a consideration of the 
systematic position of this remarkable alcyo- 
narian, some historical remarks may not be 
amiss. It is interesting to note that there is 
good evidence that another specimen evi- 
dently referable to this form had been ob- 
tained and observed by two famous English 
workers on Alcyonaria 20 years ago. In an 
elaborate work on the alcyonarians collected 
by the Siboga Expedition {Siboga-Expeditie , 
Xllld, p. 219, pi. 21, fig. 8) issued in 1931, 
we find a short account by Sir Arthur J. 
Thomson and Miss Laura M. I. Dean (Mrs. 
L. M. 1. Macfadyen) entitled, "Deceptive 
Fragments," as follows: 
Stat. 60. Haingsisi Reef. 1 Ex. 
Stat. 81. Sebangkatan, Borneo-Bank. 34M. 
Coral bottom and Lithothamnion. Sever- 
al Ex. 
Several badly preserved fragments of a 
pronounced white colour, with a marked sug- 
gestion of shrunken Alcyonium or Lohularia 
colonies, and showing on some of the 20 oids 
eight tentacles (non-pinnate however), turn 
out to be compound Tunicates, not far re- 
moved from Sarcodidemnoides. The calcareous 
spicules, minute tuberculate spherules, are 
more refractive than those of Alcyonarians; 
as an instance of deceptive convergence we 
have figured a few. 
This account and a sketch of spicules show 
quite decidedly that the so-called "deceptive 
fragment" was none other than a specimen of 
the present alcyonarian. It is small wonder 
that both authorities took it for a didemnid- 
like tunicate because of the peculiar shape of 
its spicules alone. In the group Alcyonaria, 
the form and arrangement of spicules con- 
stitute one of the most important characters 
of the genera and, often, of the species. They 
are usually represented by discs, rods, clubs, 
spindles, or capstans, all of which are simple, 
warty, or more complicatedly tuberculated or 
ramified. However, such distinctly star- 
shaped spicules resembling those in certain 
sponges and tunicates, as found in this 
PACIFIC SCIENCE, Vol. V, April, 1951 
Asterospicularia, are yet unknown in the 
Alcyonaria. In this respect, Hickson’s opin- 
ion (1930: 230) that "The characters of the 
spicules are of great value in distinguishing 
the genera, and often of the species, but they 
are of little value in the division of the 
Alcyonaria into groups of higher rank,” is 
not applicable to this case. 
In this alcyonarian, the spicules are re- 
markably constant in form and size and are 
uniformly distributed in the mesogloea, ex- 
cept on the oral side of the tentacles, and do 
not form any special polyp armature. In this 
respect this species resembles more closely 
members of the Xeniidae than of any other 
family. However, it may be distinguished 
from the Xeniidae by the presence of spicules 
in the mesogloeal lacunae; for in the Xeniidae 
the spicules are confined to the ectodermal 
layer. The mesogloeal lacunae containing 
spicules are better developed than in the 
Alcyoniidae and Nephthyidae and are con- 
stant in form; moreover, the spicules in each 
lacuna are generally more than one in number. 
In the latter families, each lacuna is rather ill- 
defined and contains usually a single spicule 
almost similar to the outer contour of the 
lacuna. 
In the mode of branching and in having 
numerous spicules scattered in the thick 
coenenchyma between the polyp cavities, this 
alcyonarian seems to be more closely related 
to the family Alcyoniidae and the genus 
Capnella of the Nephthyidae than to any 
other form, except that the mesogloea of the 
coenenchyma shows an unusually honey- 
combed structure as in that of the polyp body. 
The coelenteron, which has scattered en- 
dodermal cells and zooxanthellae without 
forming any ordinary epithelial lining, seems 
to be rather peculiar. But the endodermal 
canal system seems to differ little from that of 
the Alcyoniidae. 
The absence of pinnules in the tentacles is 
also characteristic, and is certainly note- 
worthy, since the pinnate tentacle is one of 
