MAEINE ALG^ OF THE 'SEALAEK' EXPEDITION. 139 



Peyssonnelia, Decaisne. 



Siibgen. EuPEYssoNNELiA, n. subg. 



HypotliallTis fills arete iuuctis, flabelli modo fusls, maxlme erectis 



1. Peyssonnelia coccinea, J. Ag. 



J. Agardli, Epicrisis Floridearum, 1896, p. 385. 

 De Toni, Syll. Alg. vol. iv. sect. iv. 1905, p. 1695. 



Seychelles, 31 fms. ; dry specimen. 



Distribution. West coast of Australia ; Malay Arcliipelago. 



The specimen is small and sterile; it was only by comparing it with 'Siboga' material 

 that I was able to name it. 



2. Peyssonnelia Haeveyana (?), Crouan. (Plate 14. fig. 35.) 



Crouan in J. Agardli, Spec. Algarum, ii. 1852, p. 501. 

 De Toni, Syll. Alg. vol. iv. sect. iv. 1905, p. 1694. 



Saya de Malha, 55 fms., on several dry, calcareous, little pebbles. 



Bistrihution. Coast of Prance, near Brest. 



The specimens are of a bright red colour and adhere firmly to the substratum; they 

 approach both P. conchicola and P. Harveyana, but on account of the large cells of the 

 hypothallus I feel inclined to regard it as P. Harveyana. With regard to distribution, 

 it is more likely that they belong to P. concJiicola, an inhabitant of the Eed Sea. 



The specimens are all barren, and it is impossible to name them with certainty. 



3. Peyssonnelia c aloe a, Heydr. 



Heydrich, " Neue Kalkalgen von Deutscli Neu-Guinea " in Biblioth. Bot. von Frank u. Luerssen, 

 1897, p. 10. 



Egmont, reef ; in alcohol. 



Coin Per OS ; in alcohol. 



Distribution. Tami, near German New Guinea ; Malay Archipelago. 



The specimens bear nemathecia with tetrasporcs. 



4. Peyssox^elia polymoepha (Zan.), Schmitz. 



Porm Gaedineei, n. f.— Thallo primo adhserente, delude a substrato soluto, tubera 

 forma diversa, sed superficie l^vi formante, colore parum rubro cum siecatus est. 

 Hypothallo ceUulis longis 3G-4i-C0 ^u, latis 8-10-16 m- Perithallo constante e 

 seriebus cellularum sursum directarum, cellulis infimis majoribus, cellulis superiori- 



bus minoribus, longioribus aut brevioribus quam latis ; latis 16-20-24 ^. Org 



fructificationis 



D 



Amirante, 30, 45-80 fms. ; dry specimens 



The specimens from Amirante are nearly allied to ]? . polymm-pha . but the loose thali 



=lre smaller and the crusts are thinner than in the typical specimens of that species The 



anatomical structure of tlie two alga; is much alike, as far as the vesetative thallus is 



