The Branched and Unbranched Freshwater Sponges. 269 
of the species was named by pointing out that the species can- 
not stand ; but all true workers in natural history, who know 
the extreme difficulty of a complicated synonymy, will recog- 
nize the absolute necessity of preventing such complication in 
all cases where it is possible. 
I am, Gentlemen, 
Yours obediently, 
JOHN J. QUELCH. 
XXX.—The Branched and Unbranched Forms of the 
Freshwater. Sponges considered generally. By H. J. 
Carter, F.R.S. &e. 
ACCORDING to my own actual experience as well as that of 
others, there are two distinct forms assumed by the freshwater 
sponges of England, viz. one stipitate, long-branched, and of 
a brown colour, and the other sessile, spreading, unbranched, 
and of a light fawn-colour when dry. The former has been 
called “ Spongilla lacustris,” and the latter “ Spongilla flu- 
viatilis ;” but as they both grow in still as well as running 
water (that is, in lakes and docks as well as rivers) they 
were more or less confounded, until Lieberkiihn definitively 
settled the differences between them, by pointing out that the 
former was characterized by the presence of a little, spined, 
curved acerate; and the latter by an amphidisk or birotulate 
spicule. 
That the branched species was recognized as such by the 
earliest authority on Spongilla, viz. Plukenet, in 1696, is 
known by his having used the term “ ramosissima”’ in his 
description (‘ Almagestum Botanicum,’ p. 356); while Lamarck, 
in 1816 (An. sans Vertébres, t. 11. p. 100), changed this to 
“amosa,”’ instancing at the same time Plukenet’s represen- 
tation “ t. 112. fig. 3,” and Hsper’s “t. 234” as illustra- 
tions of the species. Hsper’s “ tab. 23” represents undoubt- 
edly, under the name of ‘‘ Spongia lacustris,” the branched 
form of the freshwater sponge which we call ‘ Spongilla 
lacustris” at the present day. . 
It is true that Lamouroux, in 1816 (‘ Hist. des Polypiers 
flexibles,’ Engl. transl. 1824, p. 147), introduced the name 
“ Ephydatia” (épvddtios, of the water) for the freshwater 
sponges; but as Lamarck used that of ‘‘ Spongilla” about 
the same time for the same organisms in his ‘ Hist. des An, 
sans Vertébres,’ without any allusion to Lamouroux’s term, 
