88 SPONGES 
hand, into the fibro-corneous Sponge filled with its mucil- 
aginous fishy slime, and on the other, into the fleshy 
Tethya, in whose oscula the first signs of an obscure irri- 
tability show themselves. Sponges therefore appear to be 
true zoophytes; and it imparts additional interest to their 
study to consider them, as they probably are, the first ma- 
trix and cradle of organic life, and exhibiting before us the 
lowest organizations compatable with its existence. (“ His- 
tory of British Sponges and Lithophytes, pages 68-69.”) 
About the middle of the present century, however, the 
discovery of the cilia and collar cells, with their accompa- 
nying whip-like pseudopoda settled forever the question of 
the animality of the sponge. 
The first to call attention to these organs, was Grant 
in England, about 1841, followed by Bowerbank in 1852. 
Dujarden and Carter in 1854, Huxley in 1857. In Amer- 
ica, Prof. H. J. Clark announced the discovery of the cilia 
cells in Fresh Water Sponges in 1868. This was con- 
firmed by H. J. Carter in 1870. 
