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TRANSLATIONS. 
Contributions to the History of the Development of the 
Spongill^. By N. LiEBERKijHN. (Miiller's ^Archiv/ 
1856, pp. 1—19, 319—414.) 
Of the above long and valuable communication we have 
space to give only the following abstract. 
The constituents of the Spongillce, which have up to the 
present time attracted the attention of observers, are the 
following : 
1. The skeleton, consisting of siliceous spicules of 
various forms. 
2. The interstitial gelatinous substance. 
3. The gemmulcBj as they are termed, furnished with 
a pore, and having either a smooth shell or surrounded 
by amphidiscs. 
4. Motile corpuscles occurring at certain seasons, and 
which are supposed to effect the reproduction of the 
sponge, and which, according to Hogg, move in conse- 
quence of an endosmotic action, and, according to 
Laurent, by cilia. 
As regards the marine sponges. Grant notices similar cor- 
puscles, which are ciliated at the anterior end, but not 
posteriorly ; Quekett, however, states that he is unable to 
confirm this observation, and gives a totally different exposi- 
tion of the mode in which reproduction is effected. Sper- 
matozoa have been described in Tethyum by Huxley, and by 
Carter in Spongilla. 
Lieberkiihn's observations were almost exclusively confined 
to Spongilla fluviatilis. 
1. With respect to the skeleton, Lieberkiihn observes that 
the spicules are not united at the base by a siliceous material, 
as stated by Meyen, but by a substance destructible by heat. 
The spicules are usually arranged in aggregate bundles, 
which meet point to point at an obtuse angle, and project 
slightly above the surface of the sponge. 
Minute portions of the gelatinous substance exhibit under 
the microscope amaeba-Uke movements, respecting which it 
is unknown whether they are vital phenomena, as supposed 
