Ser. MELANOSPERME^. ( 61 ) Fam. DICTYOTEiE. 



Plate CLII. 

 CHOKDA mhVM.—Lamour. 



Gen. Char. — Frond cartilaginous, simple, filiform, cylindrical, tubular, the tube divided 

 at regular intervals by transverse septa. Fructification : obconical spores, forming 

 a dense stratum over the whole external surface of the frond, and "mixed with 

 elliptical antheridia (?) " Name from chorda, "a chord." 



Chorda Jihim. — Frond much elongated, attenuated to each end, very 

 lubricous, and everywhere covered with scattered confervoid hairs ; no 

 external constrictions at the septa. 



Chorda filum. — Lamour, Ess. p. 26 ; Lyngh. Hyd. Ban. p. 72, t. 18 ; Hooh. 

 in Fl. Lond. N. S. t. 204 ; Ch-ev. Alg. Brit. p. 47, t. 7 ; Hooh. Br. 

 Fl. vol. ii. p. 276 ; Wyatt, Alg. Danm. No. 159 ; Kiitz. Phyc. Gen. 

 p. 334, t. 29 ; Harv. in Mach. Fl. Rib. part 3, p. 174 ; Harv. P. B. 

 plate 107 ; Harv. Man. p. 31 ; Harv. Syn. p. 29 ; Atlas, plate 8, 

 fig. 31; Harv. N. B. A. part 1, p. 98. 



Chordaria filum. — Ag. Syn. p. 13 ; Hooh. Fl. Scot, part 2, p. 98. 



SCYTOSIPHON filum. — Ag. Sp. Alg. vol. i. p. 161 ; Ag. Syst. p. 257; Orev. Fl. Edin. 

 p. 288 ; Sjmng. Syst. Veg. vol. iv. p. 328 ; Endl. 3rd Suppl. p. 25 ; 

 /. G. Agardh, Sp. Gen. Alg. vol. i. p. 126. 



Fucus filum.— Linn. Sp. PI. p. 1631; Stach. Ner. Brit. t. 10; Turn. Hist. t. 86 ; 

 E. Bot. t. 2487. 



Fucus tendo. — Esper, t. 22. 



Ceramium filum. — Roth, Cat. Bot, vol. i. p. 147. 



Var. /3. tomentosa. — Small size, densely covered with olive-green hairs. 



Harv. P. B. plate 107 ; Harv. Man. p. 31. 



Chorda tomentosa. — Lyngh. Hyd. Dan. p. 74, t. 19. 



Hab. — On rocks, stones, and old shells from just within tide-mark, to the depth of 

 twenty fathoms. Annual. Summer and autumn. Very common. 



Geogr. Dist. — North Atlantic and North Pacific, abundant ; coast of Brazil. 



Description. — Eoot, a very minute disc. Frond three to six or even 

 " forty" feet in length, and from one to three lines or more in diameter 

 in the middle, very much attenuated to the base, and gi-adually tapering 

 to a rather acute point, everywhere covered, when young, with scattered, 

 pellucid, gelatinous hairs, from one to three-quarters of an inch in 

 length ; when old these mostly disappear, the fronds becoming more 



