(106) 



two very short invohxcral spines. Tetraspores scarcely immersed in the 

 under side of similar branchlets. 



A curious and interesting species, and one of the best marked and 

 most satisfactory perhaps of this difficult genus, and well characterised 

 by its peculiarly an-anged tetraspores, and very patent branching. It 

 has also, as Professor Harvey remarks, a peculiarly harsh and rigid feel, 

 very unlike the other species of this section of the genus. The arrange- 

 ment of the tetraspores is very peculiar, and sti'ongly marks the species, 

 being placed two or three together on the under side of slender, short, 

 simple ramuli, and are so prominent that they may be said to be 

 attached rather than immersed. The species seems to delight in the 

 sandy or somewhat muddy shores of rather sheltered bays, and is 

 perhaps not unfrequent, although few localities have been yet recoi'ded, 

 and these are chiefly confined to the Irish coast and the south and 

 west of England. 



Although not disposed to build a species, much less a genus on the 

 presence or absence of a few evanescent hairs, yet we feel assured that 

 several forms equally well marked as those already distinguished as 

 species, may still reward the labours of the careful observer, in this 

 rather puzzling but beautiful tribe of plants, and we would earnestly 

 invite the attention of observers and collectors to a field likely to reward 

 them with an abundant harvest. 



EXPLANATION OF PLATE CIV. 



Fig. 1. — Ceramium tiodosum, natural size. 

 2. — Eamulus with favellte. 

 3. — Ramulus with tetraspores. Both magnified. 

 (Reduced from Phyc. Brit.) 



