with some Remarks on the Nature of the Spongiæ Marine. 385 
tory hairs on the surface of the granules endowed with the spontaneous move- 
ment which I have just described, but was not able to discover any, although 
I employed a power of 500 diameters with a good light*.” Similar granules 
of the Chara are represented in tab. 10. in Act. Acad. Nat. Curios. vol. xiii., 
for the purpose of illustrating Dr. Agardh's memoir “On the Anatomy and 
Circulation of the Chara," * Über die Anatomie und den Kreislauf der Cha- 
ren." Thus do these granules afford additional analogy in their spontaneous 
movements to the sporules of the Ectosperma and of the Spongilla and Spon- 
gie. Since M. Donné has not succeeded in finding any cilia on the moving 
granules of the Chara hispida, and I have before shown that the sporules of 
the Spongilla fluviatilis are entirely devoid of them, though whether they 
exist on those of the Ectosperma clavata 1 am not aware, but I apprehend 
they do not: and most assuredly they do not, if those organs vibrate by the 
sole aid of a muscular+ apparatus, which, I conceive, will on further investi- 
gations prove to be generally the case; and hence the impossibility of such 
cilia ever belonging to vegetable bodies. With this view, then, of those sin- 
gular organs of locomotion, I have also stated the likelihood of those cur- 
rents, which have been noticed flowing from the moving sporules of the Sea 
Sponges, when examined under the power of 400 or 500 diameters of the best 
microscope, turning out to be caused by some other agency than that of real 
cilia. Such an agency, which I have before observed likely to be sufficiently 
effective, is that constituted by the endosmosis and exosmosis of different 
fluids, according to the beautiful discoveries of M. Dutrochet. Though I 
should remark, that the thin membranes forming the coverings or envelopes 
of the sporules and granules of plants are quite porous enough to allow the 
endosmose and exosmose fluids to act: but where papillæ or any cilia-like tu- 
bules exist, these, most possibly being hollow, will J think assist the action of 
those fluids, and so increase the currents by which locomotion is supposed to 
take place. And this agency, I conclude, will probably be found general in 
See M. Donné on the Cause of the Circulation of the Chara, p. 153, in the Lond. and Edinb. Phil. 
Mag. for August, 1838. 
t Dr. A. Farre mentions “muscular lobes” as being present in the gemmules of the Alcyonium 
gelatinosum, which are endowed with true cilia. 
3 E 2 
