THE GENUS POLYSIPHONIA. 293 
British Records. Norfolk coast (fide Geldart), Studland, Weymouth, 
Sidmouth, Torquay, Plymouth, Falmouth, Carrickfergus, Roundstone, 
and Jersey. 
Distribution in Europe. Atlantic shores of France. 
4. P. ogscura J. G. Ag. Alg., Med. 1842, p. 123. 
Conferva intertexta Roth, Catalecta Bot. i, 1797, p. 188, tab. 2. fig. 5; 
ii. 1800, p. 214. 
P. adunca Kütz. Tab. Phye. xiii. 1863, p. 13, tab, 40 (c-e). 
D. reptabunda Kütz. L. c. xiii. 1863, p. 12, tab. 34 (d-g). 
References. Agardh (2) ii. p. 943; Falkenberg (24) p. 500 ; Hauck (31) 
p. 244. 
Icones. Harvey, Phye. Brit. pl. 102. a. syn. 120. Kützing, Tab. Phye. l e. 
Descriprion.—Habit. Forming low tufts 1-3 cms. in height, branched 
from the base, branches being monopodial in origin. Not adhering to 
paper. Siphons. 12-18 pericentral and a large central one. Colour. 
Dark brown. Anatomy. Articulations as long as broad, or sometimes 
rather shorter. Attachment organ. Rhizoids developed in abundance by 
lateral prolifération of pericentral siphons. Well-developed discs formed 
at the extremities when a firm substratum is encountered. Reproductive 
organs. Tetraspores are intercalary in development; formed spirally in much- 
branched filaments, only one group of tetraspores occurring in an articulation. 
Antheridia and cystocarps unknown. 
P. obscura is distinguishable as having the most diminutive habit among 
British species with so large a number of siphons, The attachment organ is 
very similar to that of P. macrocarpa when the latter creeps in the sand. 
Habitat. Occurring in tufts on sheltered rocks, on the attachment organs 
of Fuci, and on smaller algæ. Very rare. 
British Records. Weymouth, Ladran Bay, Sidmouth, Mount Edgeumbe, 
Penzance, Pridmouth, Jersey, and Guernsey. f 
Distribution in Europe. Coast of Spain, Adriatic Sea. 
5, P. opaca Zanard. Syn. Alg. in Mari Adriat. 1842, p. 63. 
Hutchinsia opaca C. A. Ag. Syn. Alg. Scandin. 1817, p. 148. 
. repens Kütz. Tab. Phye. xiii. 1863, p. 13, tab. 39 (d-f). 
. virens Kütz. l. e. p. 14, tab. 41 (a-e). 
. condensata Kütz. l. e. p. 14, tab. 41 (d-g). 
. erythrocoma Kütz. l. e. p. 14, tab. 43 (a, b). 
. fasciculata Kütz. l. c. p. 15, tab. 44 (d, e). 
. umbellifera Kütz. l. e. p. 15, tab. 45 (a, b). 
. ophiocarpa Kütz. l. e. p. 15, tab. 47 (e-f). 
. tripinnata Kitz. (non Ag.) l. e. p. 16, tab. 48 (a, b). 
. macrocephala Zanard. ex Kütz. op. cit. xiv. 1864, p. 19, tab. 53 (e-g). 
. spiculifera Zanard. ex Kütz. op. cit. xiv. 1864, p. 17, tab. 49 (a-c). 
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