280 PERCY SLADEN TRUST EXPEDITION 
Fam. SPH HROCOCCACE. 
GELIDIoPsSIS, Schmitz. 
1. GELIDIOPSIS VARIABILIS (Grev.), Schmitz. 
Schmitz, ‘Marine Florideen von Deutsch Ost-Afrika,” in Engler’s Bot. Jahrb. Bd. xxi. H. 1, 2, 
1895, p. 148. 
Seychelles, Long Island, reef. 
Distribution. Indian Ocean; East coast of Africa. 
2. GELIDIOPSIS RIGIDA (Vahl), Web. v. B. 
Recueil des Travaux botaniques Néerlandais, no. 1, 1905, p. 9. 
Fucus rigidus, Vahl, in Naturh. Sellskabets Skrifter, v. p. 46. 
Seychelles, reef; dry specimen. ' 
Praslin, reef; dry specimen and in alcohol. 
Diego Garcia, reef; dry specimen. 
Mahé, Cap Terné, reef ; dry specimen. 
Distribution. Common in tropical seas. 
In 1904 I wrote in the above-mentioned paper that it appeared to me that the well- 
known Gelidiwn rigidum of the tropical seas was not a Gelidiuwm, but belonged to the 
genus G'elidiopsis. In 1909 Prof. Okamura gave, in his ‘“ Icones of Japanese Alge,” 
pl. 59, a figure of this alga and also of its large apical cell, and named it Gelidiwm 
rigidum. JI had failed to detect this large apical cell, and its absence was one of 
the reasons why I thought that the alga could not be a Gelidiwm; I had seen no 
cystocarps. Quite recently, in “cones of Japanese Algew,” vol. ii. No. 10, p. 188, 
Prof. Okamura has recalled his statement, made before he had seen my paper, and 
agrees with me in naming Gelidium rigidum, Gelidiopsis rigida. This alga varies in 
its ramification, the lateral branches being short or long, or sometimes unilaterally 
inserted. I believe, however, that these variations are only a form of growth. 
Gelidiopsis being a feminine substantive in the Greek language, the adjective should 
have the feminine ending, and I made an error when I called the alga Geliddopsis 
rigidum in 1904. 
GRACILARIA, Greville. 
1, GRACILARIA COMPRESSA (Ag.), Grev. 
Agardh, Species Algarum, 1823, p. 308. 
Greville, Algze Britann. 1830, p. 125. 
De Toni, Syll. Alg. vol. iv. sect. 11. 1900, p. 438. 
Aymirante, 25 fms. 
Distribution. Atlantic Ocean ; Mediterranean ; Gulf of Mexico. 
The specimen is rather slender for G. compressa and scantily branched, but I assume 
