42 OPINIONS AND DISCOVERIES 



fills the hollow of the sponge." All these sponges are com- 

 posed of a fibrous skeleton and a jelly which penetrates and 

 lines the whole, although it varies much in quantity in dif- 

 ferent species ; and he makes the important remark, that at 

 certain seasons it contains a more liquid portion full of 

 granules. The gelatinous portion, he says, forms the least 

 part of the sponge, and is copiously filled, at least in har- 

 vest, when his observations were mostly made, with a liquid 

 matter which flows out on the slightest pressure. This li- 

 quid is sometimes of a dififerent colour from the jelly, and 

 consists in a great measure of gi'anules. These are found 

 principally in the interior between the fibres, for they are 

 scarcely to be observed in the slimy exterior coating, nor 

 was there any order in their distribution. Olivi and Vis 

 have considered this fluid to be different in kind from the 

 thicker slime, but it appears to Schweigger to diflfer merely 

 in its degree of consistency. It is probably analogous to 

 the fluid granular matter contained in the tubular stems of 

 the polypiferous Sertulariadse, and as the gemmules of 

 these hydraform animals are merely developed and detach- 

 ed portions of this matter, it would seem to follow that the 

 granulous fluid of the sponge is really its seed. * 



Mr J. E. Gray, in 1824, argued earnestly against the 

 animality of sponges-f The contradictory statements and 

 authority of preceding writers, which he collected together, 

 were pretty equally balanced in relation to the presence 

 or absence of any animal faculty ; and the argument educed 



• Beobachtungeti auf Naturhistorischen Reisen von August Friedrich 

 Schweigger. Berlin, 1819: and his Handbuch der Naturgeschichte. 



Leipsig, 1820. 1 need scarcely call attention to the sameness of 



Schwcigger's \dews of the propagation of sponges with those given in 

 Chap. I. of this volume. 



t Zoological Jounial, i. p. 46-52. 



