OF THE NATURE OF SPONGES. 59 



pierced with holes, and with the microscope we see that the 

 meshes enclose some slender, transparent, coloiu-less tubes, 

 divided by septa at measured distances. Sometimes we can 

 see these tubes or sacs project like little points on the 

 membrane enveloping them ; often it is a little filament 

 which is enveloped ; sometimes there are several of them, 

 and the structiu*e in general is not very regular. 



The structure of the Spongia officinalis, and many others 

 newly taken from the sea, is very similar ; and although 

 sporules have not been detected in these species, yet their 

 structm^al analogousness to the Spongilla, and the absence 

 of polj-pes, ought to induce us to arrange them with the 

 Algae. Ehrenberg has told ]\I. Link that he had found 

 sporules in several sponges of the Red Sea. As for the 

 circulation through them described by Dr Grant, Link is 

 disposed to compare it to the movements of the liquid be- 

 tween the articulations of the Chara, and wliich, therefore, 

 is no proof of the animality of the sponge. The feculent 

 matter mixed with the effluent current is only something 

 membranous, and merely accidental. True Dr Grant had 

 observed moveable ova in the Spongia jianicea, but this 

 sponge which, says Link, is unkno^ni to me, is not a na- 

 tive of the English shores, where we find only the Al- 

 cyonium paniceum. And even if ova endowed \s\Xh inhe- 

 rent powersof motion were found in sponges, that fact would 

 not prove their animal natiu-e, for several observers have 

 remarked very sensible movements in seeds, especially in 

 those of the Conferva. Link believes that the absence of 

 polypes, the existence of sporangia in Spongilla, the ana- 

 logy between this one's structure and the true sponges, 

 are sufficient reasons for separating the " Spongoidees" from 



