146 THE MARINE BOTANIST. 



midenhrandtia. Frond cartilaginous, not stonj^, 



forming a crustaceous expansion. 

 Hapalidmm, Frond plane, transparent, composed 



of cells radiatino* from a centre. 



CORALLINA. 



Named from Coralium, coral, which these plants resemble. 



Frond filiform, articulated, branched (mostly 

 pinnate) coated with a calcareous deposit. Fructi- 

 Jication, turbinate or obovate, mostly terminal ; cera- 

 midia, pierced at the apex by a minute pore, and 

 containing a tuft of erect, pear-shaped, or club- 

 shaped, transversely parted tetraspores. 



CORALLINA OFFICINALIS.— COMMON 

 CORALLINE. 



This is an exceedingly abundant species, growing 

 in rocky pools ^ the colour, when fresh, is a dull 

 purple, soon becoming white on exposure to the 

 atmosphere. From two to six inches high, arising 



