( 148 ) 



slightly contracted, Favellee unknown to us. Tetraspores elliptical, 

 cruciate, formed from the metamorj^hosis of the lower pinnse^ sessile or 

 veiy shortly stalked. Substance somewhat flaccid, and not very per- 

 fectly adhering to the paper in drying. Colour, a rather dull red. 



This very pretty species is best known from its congeners by its 

 sparingly branched fronds, the long, slender, opposite or cruciate ramuli, 

 and their equally slender and numerous pinnae, all of nearly the same 

 length, giving the branches and the ramuli a linear outline. The densely 

 bushy apices of the ramuli will further serve to distinguish it, as they 

 add greatly to the beauty of the plant. The length of the joints is rather 

 variable, but those of the pinnse are much shorter in proportion than 

 those of the other parts of the plant. 



Its fixvom-ite habitat seems to be the low sand or rather mud-covered 

 rocks between tides, where from its small size, and being often partially 

 covered with mud, it may escape detection, but the beauty of its 

 delicate and minute fronds will well repay the trouble of a little 

 searching in its rather obscure haunts. 



1 



CALLITHAMNION CRUCIATUM. 



EXPLANATION OF DISSECTIONS. 



Fig. 1. — Ramulus with tetraspores. 



2. — Tetraspores from same. Both magnified. 



