Gray on Sponges. 49 



j4xis^ Fibraeinnumerre, coroeae, flexiles reticulatlm contextae et con- 

 nexae. Crusta gelatine subviva fibras vestiens jugacissima in po- 

 lypario e mari emerso partim elapsa evanida, Polypi ignota ; ob- 

 serving at the same time that he considers them as the most imper- 

 fect, and in fact the end of animated nature ; but his idea of the 

 similarity of this genus to Alcyonium must have been caused by his 

 only having been able to compare dried specimens, for when these 

 two genera are fresh and alive they are exceedingly different, the 

 one offers a fibrous mass covered with a slippery gelatinous mucus 

 like the white of egg, without any traces of organization ; while 

 the Alcyonium, on the contrary, offer a more or less solid mass sus- 

 ceptible of slight motion, with distinct regular cells, in which the 

 polypes are contained, and out of which they appear in still water, 

 though indeed when dry the two genera are so similar, that seve- 

 ral of the Alcyonia have been considered as sponges, and vice versa ; 

 but Lamarck has, I believe, with very little reason, separated 

 the fresh water species and placed them in a different part of his 

 system, near the Tubulariae. 



And again at the beginning of this century, Ave have such men 

 as Targioni, Tozetti, and Spalanzuni returning to the old doc- 

 trine, and persisting in regarding the sponges as belonging to the 

 vegetable kingdom, to which theory, as I have before stated, La- 

 mouroux appears to incline. Some chemical zoologists have classed 

 the sponges with the animal kingdom on account of the odour 

 which they emit when they are fresh, and when they are burnt ; 

 but these characters are fallacious, for most of the marine plants 

 emit when burnt an odour analogous to that of animal substances, 

 which appears to originate in the simplicity of their structure and 

 their habitation. 



With this difference of opinion who can be right ? we have names 

 of equal authority in support of their being vegetables, animals 

 themselves, and the habitation of animals ! But upon examination 

 we shall find that there is much more reason to consider them as 

 vegetables, for those who regard them as animals always speak of 

 their being excessively torpid, and indeed so torpid that not one 

 of them gives us any reason for believing that they have themselves 

 seen them move ; and Lamarck, who considers them as polypiers 



Vol. I. D 



