272 The Branched and Unbranched Freshwater Sponges. 
Lastly, there is the inference that these granuliferous cells 
(for the granules are very large, spherical, and sharply de- 
fined) may be spermatic alone, and that Uruguaya corallioides 
may be nothing more than the male of a dicecious sponge ; 
while it then becomes questionable whether a male form pro- 
duces any statoblasts. 
Miklucho-Maclay has long since given a series of illus- 
trations (Mém. de l’Acad. Imp. de Se. St. Pétersbourg, 1870, 
t. xv. no. 3, p. 1, Taf. 1), in which we find Pallas’s Spongia 
baicalensis again represented (fig. 5); but here under the 
name of “ Veluspa polymorpha, var. baicalensis” (p. 8), as 
derived from the marine form Spongia oculata, Pallas, 
of 1766,= Chalina oculata, Bk., of 1866, and the typical ex- 
ample of my order Rhaphidonemata ; but although the least 
like of the branched freshwater sponges to Chalina oculata 
is Spongilla lacustris, it comes nearest in the form of its 
spicule, which is acerate, smooth, curved, fusiform, and sharp- 
pointed in both ; while in Lubomirskia baicalensis it is spined, 
and in Uruguaya corallictdes not only microspined but much 
curved, cylindrical, and round at the ends. On the other 
hand, in the general form of the sponges themselves it is 
almost impossible to be more like Chalina oculata than are 
Uruguaya corallioides and Lubomirskia baicalensis. 
Still it is not what a sponge may have been, but what it 
as, that the student should chiefly concern himself about, and 
then it will be found inconvenient to put sponges bearing 
statoblasts with those which have none; hence my family 
Potamospongida is provisionally placed by itself at the 
end of my order Holorhaphidota, to which in texture Spon- 
gilla otherwise belongs. The typical form of the spicule 
in the Rhaphidonemata, just described, is identical with 
that of the Renierida, which is the first family of my 
Holorhaphidota ; but the main support of the fibre in the 
former is the horny investment, while in the latter it is the 
axial core of spicules; thus the Rhaphidonemata are resilient 
and the Holorhaphidota may be crushed. 
P.S.—Since the above was written, I have received (15th 
March) a packet from Dr. W. Dybowski (Niankow, near 
Novogrodek, in Minsk), in which he has kindly sent me 
copies respectively of his paper on the freshwater sponges of 
Russia, in the thirty-ninth vol. of the Imp. Acad. of Sc. above 
mentioned ; of a notice of others sent to him by Prof. P. T. 
Stephanow, of the University of Kharkow, which he communi- 
cated to the Natural History Society of Dorpat in February 
1883, among which is a new species from a little lake called 
