158 BRITISH IJESMIDIE^. 



5. D. Baculum (Breb.) ; segments very slender, having a solitary and 

 conspicuous inflation at the base, otherwise linear ; vesicles in a 

 single series. 



Closterium Baculum, Brebisson, Alg. Fal. p. 59. t. 8 (1835). 



Closferium trabeculoides, Corda, Observ. Microscop. sur les Animal, de 



Carlsbad, t. 6. f. 44 (1840). 

 Closterium Sceptrum, Kiitzing, Phycologia Gertnanica, p. 133 (1845). 

 Docidimn Baculum, Brebisson, in lit. cum icone (1846). 



Common. Carvarvon ; Dolgelley ; near Lampeter ; Penzance, &c., /. R. 

 Ashdown Forest ; near Storrington, &c., Sussex, Mr. Jenner. Near Bristol, 

 Mr. Thivaites and Mr. Brootne. Aberdeenshire, Dr. Dickie and 3Ir. P. Grant. 

 Ambleside, Mr. Sidebotham. Rochdale, Mr. Coates. 



Falaise, Brebisson. Carlsbad and Prague, Corda. United States, Bailey. 



Frond very slender, many times longer than broad, distinctly constricted at 

 the middle. Suture strongly marked, but hav-ing no projections at the mar- 

 gins. Segments with a solitary inflation at the base, otherwise hnear, the 

 ends truncate and without tubercles. 



Docidium Baculum may be readily recognized, as it is more slender than 

 any of the preceding species, and its inflations are more developed. 



Length of frond yIt ^^ ^^^ ^^^'^^^ ' greatest breadth yttt » breadth at m- 

 flation YoVs ? breadth at end ^^^. 



Tab. XXXIII. fig. 5. a, b. fronds with endochrome ; c. empty frond mag- 

 nified 400 times. 



6. D. minutwn ; frond slender, slightly constricted at the middle; 



segments linear, not inflated ; vesicles in a single series. 



Dolgelley, /. R. New Forest, Hants ; and Parham Old Park near Stor- 

 rington, Sussex, Mr. Jenner. 



Frond minute, smaller than those of any of the foregoing species, linear, 

 the constriction often scarcely perceptible ; segments four to six times longer 

 than broad, the ends truncate. 



The smaller size and uuinflated state of Docidium minutum distinguish it 

 from D. Baciilum. 



Length of frond ~-t of an inch ; greatest breadth yttj- 



Tab. XXVI. fig. 5. a. frond with endochrome; b. empty fi-ond. 



7. D. ? asperum (Breb.) ; frond slender, cylindrical, rough with minute 

 scattered granules, neither constricted nor inflated at the middle ; 

 ends truncate and dilated. 



Docidium asperum, Brebisson, in lit. ctmi icone (1846). 



Kerris near Penzance, J. R. 



Falaise, Brebisson. 



Frond slender, twelve or more times longer than broad, rough with scat- 

 tered minute points which are best seen at the margins. Endochrome irre- 

 gular. I have seen neither vesicles nor terminal globules. 



