THE HALF-TIDE POOL. 47 



four tiny seeds), which circle a swollen branchlet, and 

 give the plant a beautiful bright red appearance. It 

 is common everywhere, and in all tide-pools. 



Ceeamium Diaphanum. — This is very lovely, and 

 found parasitic on other plants, or in shallow pools 

 resting on the sandy bottom ; about three inches long, 

 and the tuft feels soft and silky. "When floated on 

 the paper, we see its beautiful texture of transparent 

 white, stem with rosy red joints, and if in perfection, 

 with deeper red seeds in a swollen joint, three in each 

 cell; or with three bright berries supported in a 

 cradle of short branchlets, near the tips of the fila- 

 ments. 



Habitat. — On rocks and seaweeds. Winter and 

 summer. 



Ceeamiuh Ciliatum (Hairy Ceramium). — This is 

 very like the former in delicate structure, transparent, 

 with purple-red joints; but observe the hairs upon 

 each filament, because their size, position, and number 

 will decide the following species, all of them more 

 or less hairy. Here we see the hairs form a regular 

 row of prickles, all pointing upwards. This is common 

 in summer, but dies away early in the winter ; we find 

 it chiefly as a parasite on smaller Alga. 



Ceeamitjm Echiofotttm (Irregularly-spined Cera- 

 mium) . — Dark red or purple tufts of jointed filaments ; 

 will show the hairs to be irregularly scattered round 

 the joints, and very slender, needle-shaped. This is 



