798 
DE. J. S. BOWEEBAIN’K ON THE ANATOJklY 
the ‘Zoological Journal’ for June 1824, states that he saw the action of the streams from 
the oscula, but like previous writers concluded that they were organs of imbibition as 
well as excurrent organs. And it was not until the excellent and accurate “ Observations 
and Experiments on the Structure and Functions of the Sponge ” were published in the 
Edinburgh Philosophical Journal, vols. xiii. and xiv., by Professor Gea^tt, that a correct 
notion was entertained by naturalists of the inhalant and exhalant powers of those bodies. 
These details by the learned Professor are so full and complete as to leave but little 
room for the improvement of our knowledge of this portion of their natm-al history. 
And the facts of the imbibition of the surrounding water by the pores in the dermal 
membrane, its circulation through the internal cavities of the sponge, and its final ejection 
through the oscula, have been firmly established and acknowledged by all naturalists 
who have studied these animals closely in a living state. Dr. Geaxt has, in truth, proved 
himself to have been, in regard to the aqueous circulation in the sponge, what Haevet 
was to that of the blood of the higher classes of animal life, the first to discover and to 
publish the true mode of the circulation of the water in the animal. 
This learned and accurate observer says, “ I first placed a. thin layer from the surface 
of the S. 2 )a/pillaris in a watch-glass with sea- water under the microscope, and on looking 
at its pores I perceived the fioating particles driven with impetuosity through these 
openings ; they floated with a gentle motion to the margin of the pores, rushed through 
with a greatly increased velocity, often striking on the gelatinous networks, and again 
relented their course when they had passed through the openings. The motions were 
exactly such as we should expect to be produced by cilia disposed round the inside of 
the pores.” — Edinburgh New Philosophical Journal, vol. ii. p. 127. 
The same author, in describing the excurrent action, says, “ The Spongia panicea [Hali- 
chondria incrustans, Johnston) presents the strongest current which I have yet seen.” Two 
entire round portions of this sponge were placed together in a glass of sea-water with 
their orifices opposite to each other, at the distance of two inches ; they appeared to the 
naked eye like two living batteries, and soon covered each other with feculent matter. 
Stimulated by the recital of the observations of Dr. Geant, I have often sought these 
currents flowing from the oscula, and there is no species which I have had the oppor- 
tunity of examining in a fresh and vigorous condition in which I have not succeeded in 
seeing them. In the one observed by Dr. Geant, Ilalichondria incrustans, Johnston, 
the oscula being few in number and very large, the excurrent streams are more 
than usually powerful. In the course of my investigations “ On the Vitality of the 
Spongiadm,” at Tenby, which are published in the Deports of the British Association for 
1856, and in the “Further Report” published in the same work for 1857, I have 
described a long series of observations of the vital actions of the Spongiadse as displayed 
in Hymeniacidon caruncula and Spongilla fluviatilis, in both of which species there was 
a perfect accordance in the habits and modes of exertion of these vital actions. 
The power of inhalation appears to be exerted in the Spongiadse in perfect accordance 
with the similar vital functions in the higher classes of animals, not involuntarily and 
