Gray on Sponges. 51 



these are not the only substances which should be removed from 

 the animal to the vegetable kingdom, for the whole of the Poly- 

 piers calciferes, of Lamouroux, (except perhaps acetabularia) are 

 equally of vegetable origin, as well as several of the Alcyonia ; for 

 in fact the zoophites have been a receptacle for every simple organ- 

 ized substance which naturalists did not exactly know where to 

 place, as we may observe by Savigny having removed several of 

 the latter genus to Mollusca. With regard to the structure of this 

 curious tribe, it appears that Ellis regarded the fibres as tubular, 

 and Lamouroux in his character has "jamais tubuleuse," but upon 

 two species figured by the former author he observed, that the C. 

 oculata is formed of reticulated fibres, and the other (C.urens) of 

 fascicules of spiculae, and from these observations he appears to 

 have formed his character in the manuscript of his zoophytes, 

 which was published by Solander ; all the other authors have re- 

 garded them as a reticulated fibrous mass, covered with a jelly- 

 like substance ; and Lamarck, in speaking of the axis and crust 

 appears to refer to the same substances, he separates this family 

 into three genera, on account of their structure : first, the spon- 

 gilla, or freshwater species, which he regards as consisting only 

 of fibres ; secondly, the Tethya, which has a small quantity of 

 gelatinous crust, and the fibres rather tangled and radiating toward 

 the circumference, and the Spongia he thinks only differs from the 

 alcyonia in having a slimy and deciduous crust, but on examining 

 the sponges which have come under our observation, (not a small 

 number of species) they all appear to be essentially formed after 

 the same manner, that is to say, of longitudinally placed transpa- 

 rent fusiform spicules, which vary considerably like the species, in 

 size and in the closeness of their connection, for in those species 

 that appear to be fibrous, the fibres are composed of spiculae, unit- 

 ed together by a cartilaginous substance*, and the Spongia tomen- 

 tosa, which is the one said to be formed of bundles of spiculae, 

 by Ellis, if it be carefully examined, by breaking it from the 

 centre of the base to the circumference, the spicula will be found 

 to be disposed and slighty united into fibres, leaving cells ; but 



* Which fibres in some of the species are so small that the spiculae are not to- 

 be discovered without the assistance of a high magnifying power. 



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