5l4 G. C. J. VosmAer, 
are represented by one single spicule. There, where the long ter- 
minal extra-axial spicules perforate the dermis, they are surrounded 
by a tuft of diverging small spieules (generally styli); this is very 
characteristic for Raspaslia. 
The chief mass of spicules are long, slender styli, occasionally 
tylostyli or strongyli, generally also oxea. In the second place acantho- 
styli oceur, either dispersed in the parenchyma or with their bases 
imbedded in the spongein of the funiculi. Finally we find, as stated 
before, small styli or oxea in the peripheral tufts. 
If we compare the skeletons of these five genera, which are so 
often mixed up, we see that indeed they are very clearly distinguishable 
from each other. But we learn at the same time, that in all these 
senera sponges are described which do not belong to them. The 
confusion partly originated by neglect of careful anatomical study of 
the specimens, more especially by neglect of an examination of the 
skeleton — i. e. the study not only of the sort of spicules, but also of 
the way how they are arranged. In applying this method it will 
become evident to everybody that RınLey & Denpy were mistaken 
if they say that Awinella and Raspailia are difficult to distinguish. 
They write (1887, p. 178) about Azinella: “This is a very critical 
genus, and it is impossible to give a satisfactory diagnosis ofit. It 
comes very near to Raspailia, but the latter is conveniently kept 
distinet on account of its very characteristic, whip-like external form.” 
And again (l. c. p. 188), speaking about Kaspailia: “The most 
characteristic feature of this genus is the external form, taken in 
connection with the absence of microsclera; like Azinella, it is a 
diffieult genus to diagnose, and the two genera, as we have already 
indicated, come very near to one another.” On the contrary: Azinella 
and Raspailia are very different. They agree with regard to the 
main construction of the axis (leaving out for a moment the presence 
of acanthostyli in the latter). Whereas, however, in Azinella the 
extra-axial skeleton is composed of funiculi of styli (or modified 
styli), terminating into tufts of diverging spicules slightly smaller 
than the bulk of the spicules, we found in Raspailia the extra-axial 
skeleton composed of funiculi of long and slender styli, each funieulus 
terminating into one single far projecting, stylus, surrounded at its 
proximal part by a tuft of diverging, very much smaller styli. In 
addition to an axial skeleton, which is fundamentally the same in 
both genera, they possess an extra-axial skeleton, which is entirely 
different. We have seen before, that the external appearance of 
