86 
that all the branches, within rather large bounds, lie in a plane. However there are also 
branches, which are inserted in such a manner as to make a thick plate of the colony, rather 
than a thin plane, a mode of branching which is more or less like the former genus Arcichno- 
pathes M. Edw. Especially the branches of higher order are entirely irregular in their 
distribution and direction, except as to the angle at which they are inserted. — There are 
vere frequent fusions between neighbouring branches, in all parts of the colony even between 
the ultimate branches. In this manner an entangled mass of rather thin branches is formed. 
The degree of branching increases towards the top of the colony, so that the thickness of the 
colony is several cm. Usually the branches are inserted at right angles or almost at right 
angles with the branch of lower order. Very often the branches are curved, except the ultimate 
ones, which are usually straight. The length of these ultimate branches varies from a few 
mm. to i cm. — The diameter of the axis in the lower part of the colony diminishes very 
swiftly so that some free ending branches are spine-shaped, but in the higher part of the 
colony the axis tapers much more slowly. 
I he spines (fig. 69) are inserted almost at right angles with the axis; their distal side 
is almost straight, the proximal side is rather curved. Near the top of the spine the diameter 
diminishes at once very much, and the top-part itself is sometimes 
slightly distally inclined. The mutual distance of the spines varies 
from 330 p. to 450 p., but this value is always the same on 
one part of the axis, so 
that the regular distribu- 
Fig. 69. Apliauipathes Sibogae sp. n. Spines ^ion is not disarranged, 
on an ultimate branch; 52 X- 
There are four longitu- 
dinal rows and a very regular straight quincunx. The 
length, subequal on all sides, is 150 p..; the surface 
of the spines is smooth. There is no increase of the 
length of the spines in the neighbourhood of the polyps. 
I hey perforate the coenenchyma easily and usually the 
polyps also; often the spines are visible in the oral 
cavity (polyp on the right branch of fig. 70). 
The polyps (figs. 70, 71, 72, 73) are white, and 
visible to the naked eye as thick, white knobs on the 
lightbrown axis, just like in Brook’s genus Tylopathes. 
1 hey are placed in a single series, on one side of the 
axis, usually all of them on one side of the colony. — 
The length of the tentacles is 0.3 mm., and except 
for the lower level at which the sagittal tentacles are 
inserted there is no great difference between sagittal 
and lateral ones. The oral cone is rather low with a 
wide open mouth, the border of which is irregular, 
(indicated by dotted lines in the figures). In the latter case the oral cone itself is also 
Fig. 70. Aphanipathes Sibogae sp. n. Polyps on the 
ultimate branches; 14 X- 
or which is shut and almost invisible 
