A SUBAQUEOUS CITY. 



141 



Presently an elevation of a finely transparent 

 membraneous nature slowly appears ; wide at the 

 base, and graduating upwards, it finally tapers off 

 into a tubular or truncated cone, from which a 

 stream of water, with contained particles of other 

 matter, is shot forth with great velocity, as if from 



FIG. 25. Hypothetical Section of Spongilla. 



(After Huxley.) 



() Superficial Layer ; (b) Inhalent Apertures ; (e) Ciliated Chambers ; 

 (ft) An Exhalent Aperture ; (e) Deeper Substance of the Sponge. 



The Arrows indicate the direction of the Currents. 



the mouth of a miniature volcano, so that small 

 infusoria or other minute material coming near the 

 orifice and in the wind of the current, are caught 

 up and whirled rapidly away with it. 



So far, even with the microscope, one could 

 hardly imagine this to be a living organised being, 

 or combination of animal life; for, excepting this 



