318 EVENINGS AT THE MICEOSCOPE. 



urchin {Echinus miliaris ) ; and I might have passed 

 it by with a feeling of satiated curiosity, had I not re- 

 collected our evening's amusement. Oh, ho ! said I, 

 what a fund of microscopic entertainment is inclosed 

 in this stone box ! So I brought it home, and now pro- 

 duce it as the text of our conversazione. 



Every part is a wonder; but we must examine 

 each in order. Take the spines first. 



As we examine these organs on the animal crawl- 

 ing at ease over the bottom of a saucer of sea-water, 

 using this triple lense, we see that each is a taper pil- 

 lar, rounded at the summit, and swelling at the base, 

 where it seems to be inserted into a fleshy pedestal, on 

 which it freely moves, bending down in all directions, 

 and describing a circle with its point, of which the 

 base is the centre. Each spine is for the greater por- 

 tion of its length of a delicate pea-green hue, but the 

 terminal part is of a fine lilac or pale pui-ple. The 

 whole surface appears to be fiuted, like an Ionic 

 column, but this is an illusion, as you will see pres- 

 ently. 



I now detach one of the spines, cutting it off with 

 fine-pointed scissors as near the base as I can reach. I 

 put it, with as little delay as possible, into the live-box, 

 and examine it with a high power, say 600 diame- 

 ters. Look at it. You see the ciliary currents very 

 . distinctly ; and if you move the stage so as to bring 

 the basal portion into view, you may discern even the 

 cilia themselves, very numerous and short, quivering 

 with a rapid movement. The currents are not longi- 

 tudinal, but transverse, and somewhat peculiar. The 

 floating atoms which come within their vortex are 

 drawn in at right angles to the axis of the spine, and 



