406 



EVENINGS AT THE MICKOSCOPE. 



knife ; a circumstance which is owing to the predom- 

 inance of the calcareous element here, as you will see 

 when I extract a small portion of it, and, laying it on 

 a slip of glass, treat it with caustic potass. The micro- 

 scope now reveals a large number of spicula, far 

 lai-ger than those we have hitherto observed, and dif- 

 ferent from either sort in form. These resemble very 

 gnarled branches of oak, with the branchlets broken 

 off close to their origin, leaving ragged and staiTcd 

 ends. 



SPICULA OF COAV S PAP. 



