310 G. C. J. VOSMAER, 
distinguish a firm, more or less cylindrical axial skeleton or axis 
and a much looser peripheral or extra-axial skeleton. The ratio 
between the diameter of the axis and the whole branch is variable 
in different specimens. But the fundamental arrangement remains 
the same. As stated before, Schmipr has already observed that the 
axis is not massiv; it is composed of a large number of spongin !) 
fibres enveloping a very variable number of spicules. These elementary 
fibres I will call funiculi°); they ramify and anastomose, thus 
forming a network, together establishing a thicker string or funis?) 
(Taf. 15 Fig. 1). The soft parenchyma of the sponge, including con- 
nective tissue, canals and mastichorions enters in the meshes between 
the funieuli. As a rule this funis is, in one branch of the sponge, 
undivided and consequently represents the axis. But sometimes the 
axis of a branch contains two or (very seldom) three such funes. 
Alongside the axis funiculi diverge at rather regular intervals and, 
eradually curving, finally run towards the sponge surface at about 
richt angles to it, resp. the axis. These extra-axial funiculi not 
unfrequently are ramified and united together by spicules and a 
scanty quantity of spongin. They terminate into groups of a few 
diverging spicula, thus forming brushes (Taf. 16 Fig. 5). Examined 
from the sponge surface, the terminal brushes are seen to be ir- 
regularly dispersed; focussing a little lower one observes the spieules 
uniting the funiculi, forming an irregular network, with some more 
or less quadrangular meshes (Taf. 15 Fig. 2). 
ll. Phakellia. 
The genus Phakellia is established by BOWERBANK, who gives 
the following diagnosis (1862, p. 1108—1109): “Skeleton composed 
of a multitude of primary cylindrical axes. radiating from a common 
base and ramifying continuously, from which emanate at about right 
angles to the axes a secondary series of ramuli, which ramify con- 
tinuously as they progress towards the surface, but never appear 
to anastomose.” The type of this genus is said to be Halichondria 
ventilabrum of JOHNSTON-BOWERBANK and several other authors de- 
1) For the sake of convenience I use this word in the sense as it 
is generally taken; it is, however, quite certain that the spongin of 
Euspongia, Spongelia, Aplysina, the so-called Chalineae, Reniera etc. etc. 
is by no means the same substance. 
2) funieulus, a thin rope or thread. 
3) funis, a thick rope, composed of several threads. 
