FIJI-NEW ZEALAND EXPEDITION 83 
very well with the figures of the genus Sarcophyton, as given by 
Bourne in his article on Anthozoa.!” 
One of the most interesting forms encountered on the Makuluva 
reefs was an alcyonarian with strongly retractile branches, a thing 
that I had never heard of, except in some pennatulids, such as 
Ptylosarcus, where the stem is highly contractile, or perhaps it 
would be better to call it erectile. 
The Makuluva form looks so much like a gorgonian, such as 
Plexaurella, with erect stubby branches, that I supposed it was 
one. One of the surprises of my life came when IJ touched one 
of the branches and all of them immediately began to retract un- 
til the whole colony took on the shape of an irregularly rounded 
mass, each branch being reduced to a nodule on the general sur- 
face. The retraction was fully as rapid as that of an anemone, 
and repeated experiments showed that they always quickly re- 
sponded to a tactile stimulus. The polyps promptly retracted at 
the same time. An astonishing effect of this retraction is that the 
colony turns pale at the approach of danger—first shrinks away 
and then turns pale, like a timid maiden! The polyps are dark 
brown. when expanded, thus giving a decided brown coloration to 
the colony. The eenenchyma, however, is almost pure white and 
the retraction of the polyps exposes this surface, resulting in a 
quick change from brown to white, dotted with the brown open- 
ings into which the polyps have withdrawn. 
The polyps themselves are small, dark brown, having tentacles 
of the usual aleyonarian type with fringed margins. They are 
encrusted with small spicules of a type not at all characteristic 
of the family Nepthyide to which this form seems to belong. These 
spicules are almost uniformly double spindles, or rather double- 
stars, such as characterize the family Gorgonellide, a widely dif- 
ferent group. These double-stars have their ends covered with 
strong nodules which themselves bear several sharp points, and 
there is a smooth girdle on the median part of the spicule separat- 
ing the two stars. The tentacles are not fully retracted but are 
folded over the disk of the retracted polyps, a character diagnostic 
of the family Nepthyide, according to Bourne. However, the 
uniform spicules in the shape of double-stars, (for I found none 
of the spindles) would, it seems to me, necessitate another class- 
12 Lankester, ‘‘A Treatise on Zoology’’, part 2, fig. XII, and the text on 
p. 24 
