GEPP 
MARINE ALGA AND MARINE PHANEROGAMS. 383 
Var. mamillosa f. nuda, Web. v. Bosse, J. e. p- 382. 
Chagos Archipelago: Diego Garcia and Coin, Peros. Coetivy. In each case on reefs 
exposed at dead low tide. 
Geogr. Distr. West Indies. 
CODIACEZ. 
Copium, Stackh. 
18. Codium difforme, Kiitz. Tab. Phye. vi. (1856) p.35, tab. 99 ; Askenasy, in Forsch- 
ungsreise ‘Gazelle,’ Theil iv. Bot. (1889) p. 10; Bornet, Algues de Schousboe 
(1892), p. 55. 
Chagos Archipelago: Peros, on reefs exposed at dead low tide. 
Geogr. Distr. Mediterranean. Kerguelen. 
This species resembles in habit C. adherens, Ag., but is quite distinct in the size of 
its utricles (peripheral cells), which measure about 1 mm. in length and 150-200 « 
in diameter, while those of C. adherens do not exceed 60 » in diameter. These 
distinctions are pointed out by Askenasy and Bornet (Ul. cc.). 
19. C. ovale, Zanard. Phyc. Papuanze, in Nuoy. Giorn. Bot. Ital. x. (1878) p. 37; 
De Toni, Syll. Alg. i. (1889) p. 491. 
Seychelles, 31 fms. 
Geogr. Distr. New Guinea. 
20. C. tomentosum, Stackh. Ner. Brit. (1801) p. 21, tab. 7; De Toni, Syll. Alg. i. 
(1889) p. 491. 
Amirante, 20-25 fms. and below 25 fms. 
Geogr. Distr. Mediterranean. Atlantic. Cape of Good Hope. Indian Ocean. 
Pacific. 
This species has a wide distribution in temperate and tropical waters. But since 
many specimens of similar habit have in the past been wrongly referred to it, caution 
should be observed in accepting all the specimens so determined in large Herbaria 
without re-examination of the utricles of the plants. The shape and average size of the 
utricles, the apex of the utricle whether thin-walled or thickened, whether mucronate or 
not—these, together with habit, are the distinguishing characters of the species. 
21. C. elongatum, Ag. Spec. Alg. (1849) p. 454; Kiitzing, Tab. Phyc. vi. (1856) tab. 96 ; 
De Toni, Syll. Alg. i. (1889) p. 496; Bornet, Algues de Schousboe (1892), p. 56. 
Amirante, 20-25 fms. and below 20 fms.; Seychelles, 31 fms. 
Geogr. Distr. Mediterranean. Indian Ocean. Australia. 
In an interesting note upon this species Bornet (loc. cit.) points out that in distin- 
guishing the forms of this and of the preceding species the most trustworthy character 
is found in the respective size of the utricles rather than in the external habit of the 
plants, and that the specific limits thus assigned accord well with the ead a 
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