242 SCYTONEME^E. 



sulphureous properties, as if the hepatic gas were necessary 

 to its production and nourishment." Dillw. 



5. TOLYPOTHRIX BUFESCENS. 



Plate LXIX. Fig. 7. 



Char. Filaments minute, spreading in a thin slimy purplish 

 stratum. 



Calothrix rufescens Carm. ; Harv. in Hook. B. Flor. p. 368.; 

 Harv. in Manual, p. 158. 



Hob. On rocks under the spray of cascades, Appin: Cap- 

 tain Carmichael. 



" Crust or stratum of indefinite extent, and so thin as to 

 seem a mere discoloration of the rocks until the finger is 

 passed over it, when a certain sliminess detects the presence 

 of the plant. Filaments half a line in length, and so slender 

 as to appear mere lines under the highest power of the com- 

 pound microscope." Carm. MS. 



b. Branches adherent to the main filaments. 

 6. TOLYPOTHRIX DlLLWYNII HdSS. 



Plate LXVIII. Figs. 4, 5. . 



Char. Filaments tufted. Branches subulate., adherent to the 

 principal threads nearly their whole length. Stria3 about 

 a diameter from each other. 



Scytonema Dillwynii Harv. et Ralfs' MS. 

 Hob. Dolgelly : Mr. Ralfs. Moist rocks, co. Antrim : 

 Mr. Moore. 



This species was named by Harvey Scytonema Dillwynii, 

 under the impression that it was the Microcoleus ? Dillwynii 

 of his " Manual," and the Conf. vaginata of Dillwyn, t. 99. 

 which it is difficult to conceive from Dillwyn's description 

 that it really is. I felt much inclined to place this plant by 



