1167 
which in its turn is identical with the crusts mentioned above 
and which I believe are equivalent to Spongia sanguinea Grant, or, 
as its name should be now: Hymeniacidon sanguinea. 
In the foregoing table the variability in spiculation and in size of 
the spicules is conspicuous. The measurements are given in microns ; 
the sizes of the spicules in Bowerbank’s specimens are calculated 
from his illustrations. In the specimens marked with an asterisk, 
desmoids were found. : 
Generally two sorts of styli can be distinguished: slender and 
stout ones. In such cases this is indicated in the above table; the 
upper numbers refer to the slender ones. Often it is, however, 
difficult to make a distinction on account of the transitions. The absolute 
mininum in my specimens is 150 u, the maximum 865 u; on an 
average they vary between 210 u and 470 w. Of course the figures 
in the list do not prove much, for a much larger material is wanted 
in order to draw conclusions of importance. But it is sufficiently 
evident that the styli vary a good deal in length and that no specific 
distinction can be made on account of slight differences in size of 
the styli. If, therefore, Ridley says (1884 p. 467) that this Hymenia- 
cidon agmimata is near H. caruncula, “only the spicules are of a 
rather smaller average size”... this is for me no reason for a 
specific distinction. Topsent has already identified M. consimilis and 
H. viridans with H. caruneula. | am of opinion that the differences 
between H. imammeata Bwk., H. medius Bwk. and H. consimilis 
Bwk. are not of a specifie nature; the more so since BOWERBANK- 
Norman (1882 p. 82) state that the ‘““mammiform organs” are by 
no means always present. 
As for Maas’s Avinella crista-galli 1 suggested (1912 p. 316) that 
this sponge was not an Aavnellau. As far as can be judged from 
Maas’s description A. crista-galli is nothing but a synonym of the 
sponges mentioned above. In external appearance it agrees with 
such specimens from Naples as e.g. 888, of which I give a coloured 
illustration from the living animal in my monograph. Among the 
hundreds of sponges from Naples I examined I never saw a single 
Avinella with which it could possibly be identified; whereas the 
resemblance with several specimens of Hymeniacidon sanguinea is 
very striking. “Der Schwamm ist von ansehnlicher Grösse, bildet 
Krusten, die seitlich comprimirt und gewunden sind wie ein Hahnen- 
kamm. Die Oberffäche ist unregelmässig wellig” (Maas, 1893 p. 338). 
The skeleton, according to Maas, is composed of two sorts of spicules 
which are said to be ‘“stecknadelformig’’, but according to the figures 
these spicula are styles with some strongyla. I examined a number 
