190 Mr. J. Hogg on Dr. Nardo's Classification of the Spongire, 



XVII. — On Dr. Nardo's Classification of the Spongife, and further 

 notices of the Spongilla fluviatilis. By John Hogg, Esq., M.A., 

 F.R.S., F.L.S. &c. 



My attention having been lately called to the October Number, 

 1849, of the ' Annals and Magazine of Natural History,' 1 read 

 at p. 242, that Dr. Nardo had proposed, at the Scientific Congress 

 held at Lucca in 1843, a new classification of the Spongia, divi- 

 ding them into five families, as follows : — 



Family I. Corneo-sponffia. 

 Family II. Silico-spongia. 

 Family III. Calci-spongia. 

 Family IV. Corneo-silici-sj)ongia. 

 Family V. Corneo-calci-spongia. 



By comparing these with my " proposed divisions of the order 

 Spongice," published two years before, at pp. 5 and 6 of the Sep- 

 tember Number, 1841, of the 'Annals and Mag. Nat. Hist.,' it 

 will be seen that Dr. Nardo's classification is in most essentials 

 much the same as mine ; the only new part appearing to me to 

 be his last or fifth family, which I suppose comprises those spe- 

 cies wherein horny fibres combined with calcareous spicula may 

 have been detected ; and which, at the time of my writing the 

 communication above referred to, were not known to exist, as I 

 have stated at p. 3, from M. Milne-Edwards's observation, and 

 again at p. 6 of the same September Number of the ' Annals.' 



On a recent perusal of Mr. Carter's papers on the Freshwater 

 Sponges of Bombay, as reprinted and published in the 'Annals 

 and Mag. Nat. Hist.,' April Number 1848 and August Number 

 1 849, I found that his descriptions are not very clear, but con- 

 tain some ambiguity and difficulty ; and that the author had, 

 during the progress of his examination, changed (as other authors 

 had previously done, when engaged upon the same remarkable 

 and puzzling substances) his opinion respecting their nature. I 

 was however happy in noticing that he had confirmed my ac- 

 counts in several important particulars, especially with regard to 

 the sporidia or seed-like bodies of the spongilla, to the modes of 

 development and growth from them, and to the power of the sun 

 in tui'ning the yellow sponges green when exposed to his rays. 



Following some of the French naturalists, Mr. Carter con- 

 siders, with them, that the freshwater sponges consist of a con- 

 geries of animals identical with the infusorian Proteus (April 

 Number 1848, Ann. and Mag. Nat. Hist. p. 310), which is the 

 Amceba of Ehrenberg. Now, as I have before remarked (Linn. 

 Trans, vol. xviii. p. 397) that this Proteus, or Amceba, is an ani- 

 malcule of complex organization, possessing, according to that 



