137 
Skeleton composed of tylostyli, which are lying in all direc- 
tions, towards thc surfaco is scøn an incrcasing tøndcncy towards 
the building of only little distinet spicula-fibres or rather spicula- 
tracts, which are partly parallel 
with, partly almost in a right 
angle to the surface; the spicules 
are very mueh denser in the 
outer layers, which gives origin 
to the forming of a rather thin 
ectosome, not sharply distinet from 
the choanosome. Big and small 
tylostyli are lying pell-mell, not 
as for instance in the Suberi- 
tidae, where the small spicules 
most often are forming a separ¬ 
ate bark-layer. 
Spicules: (fig. 17a—d) 1. tyl¬ 
ostyli of two kinds; a) small 
on es, in lesser number than 
the bigger; slightly bent, of even 
thickness everywhere, except in 
the last Vs, where they are 
o 
0 / 
Fig.17. Biemma rhaphidiophora, nox.spec. 
a., slyli; ft, bases of styli; c, rhaphides; 
d, sigmata. 
evenly pointed. Length 143—208 
// most often about 195 thickness ca. 5,5—6 head beauti- 
fully marked off. b) big on es, nearly straight, most often thick- 
est a little beyond the middle, evenly and sharply pointed, pretty 
well marked head; sometimes the head is found a little outwards 
on the axis; such spicules are in faet distinet, they are a little 
longer than maximum of the other spicules, viz. so mueh longer 
as the short axis is long. Length 275—460 /i^, commonest length 
415 //, thickness ca. 5,3 p. 2. rhaphides; straight, thickest in 
the middle, from here evenly tapering towards both ends, may there- 
fore rather be called microxa. Length 46 — 52 p, thickness 1,5— 
2,5 //; these spicules are very easily overlooked. 3. sigmata, 
regular or contorted, with very short and inwards bending points; 
length very varying, from 10—65 p\ sizes of 15—20 p commonest; 
thickness 0,5—3 p\ rather unfrequent. 
This species is very interesting in having rhaphides; so far as 
