153 
The peripherical skeleton is constructed mainly of oxea. In 
accordance with the above statements about the microscopic facts, 
this skeleton is heterogeneously developed. Between the bushy 
length-rows of spicula-fibres are found very short ones, at most a 
few spicules in length and breadth, which seem to be a continu- 
ation of the transverse spicules in the axis (see above). The big- 
ger skeleton-fibres in the peripherical skeleton are extending from 
the axis at a rather acute angle; as the small ones, these fibres 
also seem to be continuations of fibres found in the axis, viz. the 
longitudinally directed; this, however, cannot directly be demon- 
strated. These fibres are rather loose in construction, and so far 
as can be seen, without spongin; they are branching and anastom- 
osing rather frequently at acute angles; the spicules are not quite 
parallel, the distal ends are directed somewhat outwards; in faet 
the fibres are constructed like those characteristic of Åxinellidae. 
Both sigmata and rhaphides are almost completely reserved for 
the peripherical skeleton. 
Spicules: (fig. 28 a e) 1. s tyli; found rather scarcely both 
in the peripherical and in the axial skeleton; they are stout, slightly 
bent at about the first third or fourth. Thickest in the middle, 
decreasing only a very little towards the basis, while the taper¬ 
ing towards the distal end is very even and constant, except 
the very point, which is rather abruptly marked off; there are 
sometimes beginnings to subtylostyli. Length varying from ca. 390 
710 fi; sizes about 480 the most common; thickness varying 
from 11 24 Styli lying in the axis have the same size, gener¬ 
ally, however, somewhat thinner and longer than the above given 
medium size, and the shape mueh more irregular, so that one 
spicule may be curved in se veral places. 2. oxea, are, as already 
mentioned, particularly reserved for the peripherical skeleton, and 
only there regularly developed. The typical shape is slightly bent 
in the middle, where also the thickness is the greatest; from here 
evenly tapering towards the two very sharp points, which as a rule 
are more abruptly marked off. I regard this as the type; but 
there are several and most varying exceptions. It is for instance 
common that the points, one or both, are so abruptly marked off 
as to make the spicule a tornota; or they may be blunt, so as to 
make the spicule rather strongyla-like; or the bending may be 
