158 Mr George W. Traill on the [sess. lii. 



16. Callithamnion polyspcrmuni, Ag. 



At 3, 7, 12, &c., at about half- tide level, on shaded ver- 

 tical rocks and on Alg;e ; always in places which are 

 uncovered for several hours daily. Annual, March 

 to October. Best months for fruit, May, June, and 

 July. Spores escape at the end of July. 



17. Callithamnion Rothii, Lyngb. 



Common on rocks near high-water mark, usually in the 

 shade, and always at places which are uncovered for 

 several hours daily. Perennial. Fruit in winter. 



18. Callithamnion secundatum, Ag. 



At 7, 8, 12, (fee, from about half-tide level to low-water 

 mark, on Ehodymcnia palmata, &c.; fine. Annual, 

 May to September. Iruit in summer. 



19. Callithamnion sparsum, Harv. 



Cast ashore on stems of Laminaria Cloustoni, Le Jolis ; 

 rare. Summer and autumn. 



20. Callithamnion Turneri, Ag. 



Chiefly at 4 and 12, on small Algne at low-water mark ; 

 always submerged. Epiphytic on Polyidcs rotundus, 

 Furcellaria fastigiata, Phyllophora Brodimi, &c. 

 Annual, May to September. Fruit in summer. 



21. Callophyllis laciniata, Ag. 



Cast ashore from deep water. Biennial. Capsules in 

 spring ; granules in summer. 



22. Calotlirix confcrvicola, Ag. 



Common, especially at 7, on small Algte in shallow 

 pools above half-tide level ; always submerged. 

 Annual, summer and autumn. 



23. Calothrix fasciculata, Ag. 



At 12, on vertical rocks near high-water niark,in the shade; 

 rare. Always inplaces uncovered for many hours daily. 



24. Calothrix pmlvinata, Ag. 



At 12, on vertical rocks near high-water mark,inthe shade; 

 rare. Sometimes epiphytic on Fucus canalicidatus. 

 Always in places uncovered for many hours daily. 



25. Calothrix scopidorum, Ag. 



At 1 and 2, on rocks near high-water mark. 

 20. Catenella Opuntia, Grev. 



Fine and abundant at 12, on vertical rocks in the shade, 



near high-water mark. Perennial. Tetraspores in 



.July. 



