cond scries : botli primary and socondnry brandies arc fiirnislicd at every joint 

 witli minute, multitid, dieliotomous, opposite or wiiorlcd ramuli, wliosc arti- 

 culations arc very sliort, and the terminal cellules acute or mucronate. Jrli- 

 ciilnlio)is of the branches oblong', nearly twice as long as broad. Tetraspo7'es 

 globose, near the ends of the ramuli, sessile. Colour a dark red-brown. 

 Suhscance firm, but soft. In drying the frond adheres closely to paper. 



In external aspect this pretty little plant is not unlike some 

 species of the group to wliicli the British C. tetfacjonum belongs ; 

 but it properly falls under the division with opposite ramuli, al- 

 though here the regular opposition is partially concealed by the 

 very unequal development of the opposing pinnse, — an inequality 

 which has suggested the specific name, disjjar. Similarly un- 

 equal opposite pinnse are of frequent occurrence on the genus 

 Ftilota, and are found also in two species of Ballia. 



I do not know any species of Callithamnion with which this 

 plant need be contrasted. It is not uncommon, growing in the 

 stems and branches of the Fucoid AlgaD. 



Fig. ]. Callithamnion dispar, — the naliwal size. 2. Portion of a branch, with 

 its unequal ramuli, a long ramnlus opposing an abortive one. 3. Kamel- 

 • lus bearing tetrasjwres. llamellus bearing antheridia ? : — majnijied. 



