408 
PACIFIC SCIENCE, VoL VIII, October, 1954 
Dr. Yamada believes this is an undescribed 
species but does not venture to name it in- 
asmuch as the specimen is incomplete. 
Sargassum sp. 2 
Fig. 22a, h 
LOCAL DISTRIBUTION: In drift, Sta. 2 
(11358); also observed in drift on the seaward 
shore of lie de Tre. 
Sargassum sp. 3 
Fig. 22c-^, p, q 
LOCAL DISTRIBUTION: On rocks, Sta. 3 
(11168), Sta. 10 (11346). 
Sargassum sp. 4 
Fig. 22/,/ 
LOCAL DISTRIBUTION: In drift, Sta. 11 
(11352). 
RED ALGAE 
Key to the Genera of Khodophyta 
1. Thallus calcified, at least in part 2 
Thallus uncalcified 16 
2. Thallus crustose 3 
Thallus not crustose, the erect parts 
branched, free. 10 
3. Tetrasporangia borne in nemathecial sori 
Peysonnelia (in part) 
Tetrasporangia borne in enclosed con- 
ceptacles 4 
4. Thallus monostromatic or essentially so 
5 
Thallus polystromatic 6 
5. Epiphytic, prostrate; conceptacles 150- 
200 fi in diameter Fosliella 
Not epiphytic, partially free; conceptacles 
1 mm. or more in diameter . Lithoporella 
6. Roof of sporangial conceptacles perfor- 
ated by few to many pores 
Lithothamnium 
Roof of sporangial conceptacles perfor- 
ated by a single pore 7 
7, Heterocysts present and prominent . .... 
Hydrolithon 
Heterocysts absent or obscure. 8 
8. Thallus a simple crust 150-2,500 n thick 
9 
Thallus with prominent excrescences or 
branches Lithophyllum (in part) 
9. Sporangial conceptacles 500-600 jj, in 
diameter Neogoniolithon 
Sporangial conceptacles 100-130 ju in 
diameter Lithophyllum (in part) 
10. Calcification discontinuous, the thallus 
jointed 11 
Calcification complete or incomplete but 
not discontinuous; thallus not jointed 
12 
11. Conceptacles terminal; segments less 
than 225 jjl in diameter Jania 
Conceptacles lateral; segments over 250 
JJ, in diameter Amphiroa 
12. Thallus flabellate Titanophora 
Thallus cylindrical to ligulate ..13 
13. Thallus calcified very lightly only at the 
base Dermonema 
Thallus lightly to heavily calcified 
throughout except at young tips . . . .14 
14. Thallus soft, + — lubricous .. Liagora 
Thallus H rigid, not lubricous .... 1 5 
15. Thallus provided with whorls of filaments 
extending from the cortex 
Actinotrichia 
Thallus smooth, or, if extended filaments 
