The Scottish Naturalist. 383 



the same thread or less frequently on distinct threads. In the 

 British specimens of V. sphaerospora (as in those gathered by me 

 at Kiel), the antheridia were often, but not always, at a distance 

 from the oogonium. I met with forma monoica as well as f. 

 dioica in Scotland : in the estuary above Portree, in Skye, and at 

 Ballachulish ; in England, at Greenod, in Lancashire (sparingly 

 on sand) ; in immense quantity in the river, one mile on both 

 sides of the bridge at Maldon, in Essex, and in smaller patches on 

 the shore of the Thames at Kew Gardens (consequently in some- 

 what brackish water). In the specimens of V. piloboloides in E. M. 

 Holmes' " Algae Britannicae rariores exsiccatse," No. 50, (from 

 Weymouth), I have met only with V. sp/iaerospora, (the not 

 brownish oospore filling up the oogonium, in one example the 

 curved antheridium was attached directly to the oogonium), and 

 not with V. piloboloides. The latter species also may perhaps 

 exist in the cited No., though I was not able to meet with it 

 there. 



Filaments of V. sphaerospora 0,35 — 60 m.m. in diam. Oospores 

 o, n — 13 m.m. in diam. Antheridia 0,060 — 75 m.m. broad, by 

 0,150 — 165 m.m. long. Oospores in the specimens from Appin 

 0,07 — 0,105 m.m. in diam. 



V. synandra Woron, in " Botan. Zeitung," 1869. 



Filaments 0,04 — 9 m.m. in diam. Oospores 0,100 — 125 m.m., 

 broad by 0,125 — r 7° m.m, long. The androphore 0,05 — 6 m.m., 

 broad by 0,075 — 9° m - m - long. 



V. litorea Hofmann Bang et Ag. (in Agardh " Spec. Alg," 1822, 

 p. 463; Nordst. -'Bot. Not," 1879, p. 181, tab. 2, fig. 1—6; 

 V. clavata Lyngb. " Hydroph. Dan.," 1817, p. 78, tab. 21, D 

 exclus. omn. synonym). 



Filaments 0,05 — 9 m.m. in diam. Antheridia about 0,55 — 65 

 m.m. long, by 0,055—90 ( — 125) m.m. broad. Oospores, rather 

 small, 0,11 — 15 m.m. broad, by 0,13 — 17 m.m. long. Very few 

 oogonia with oospores were seen by me. I gathered antheridia, 

 but no oospores, in the river, between Dolgelly and Barmouth 

 (near Ferry station), in North Wales, i8 27 / 6 85 ; at the other places, 

 both antheridia and oogonia, but very few oospores. 



In the Herb. Agardh. I have seen a specimen of " V. longipedun- 

 culata " with description and figure, gathered by " David Moore " 

 (in Ireland ?) I never saw a description of that species published. 

 It was the female plant of V. litorea (cfr. "Bot. Not.," 1879). 



