28 
Halichondria mammillaris”’. 1 have no objeetion to the fact that 
Bowerbank identifies his Sponge with Montagu’s; but why has he 
changed the name penicillus into the latter mammillaris? Probably 
because he identifies his Sponge also with Johnston’s Hal. mammillaris 
and that this author identifies his specimen with Mulier’s Spongia 
mammillaris. Now it seems to me 1°. that Johnston was not right in 
doing so, for I have Sponges from the coasts of Norway wich 
much more resemble the specimens of O. F. Müller and which are 
not identical with the Sponge under description; 2°. that Bowerbank 
was not right of identifying his Sponge with Johnston’s Hal. ma- 
millaris. Bowerbank says in his diagnosis (Mon. II, pag. 71) that 
the spieules are: „fusiformi-enormi-spinulate, rarely fusiformi-acuate”. 
And Johnston says (pag. 143) „The spieula are long and straight 
fusiform, sharp at both ends” and pag. 142: „spicula fusiform 
acute at both ends”. Thus in comparing these two facts, it will 
be apparent to everybody that Hal. mamillarıs Johnst. and Poly- 
mastia mammillaris Bwk. are not identical. 
As I have said I possess Sponges which resemble very much 
the Spongia wmamillaris of Müller (Zool. Dan. IV, pag. 44, Tab. 
CLVIII, figg, 3 and 4). This Sponge is probably a Polymastia 
too. But the tubes are much shorter and stouter, and not so fre- 
quent. 
Now, according to Oscar Schmidt, Balsamo Orivelli’s Suberites 
appendiculatus is identical with Bowerbank’s Polymastia mammillaris. 
I am by no means sure if this is really the same species. Gray 
has named this Sponge Pencillaria mammillarıs, but I think it is 
not necessary to change the generic name. 
With all these, de Merejkowky’s Rinalda arctica very much 
agrees. But why has Schmidt erected the genus Rinalda for his 
R. uberrima? Is this not a Polymastia? It appears to me that the 
generic name Rinalda is superflous, and that again R. arctica de Merejk. 
is a Polymastia even probably identical with the P. penieillus under 
description. The Sponge of the Russian investigator is described as 
follows: „Cette eponge, dont la forme est ordinairement spherique, 
legerement aplatie, atteint dans la plupart des cas 4 Ctm. de dia- 
