$18 2. THALASSIOPHYT. — Pi. cell. aph. 
C. Thallus with a continued fibrous axis; bark chalklike, 
jointed. Corallidese. 
Thallus forked ; joints cylindrical ......... Janta. 39. 
Thallus three-forked ; joints wedgelike Coratuina. 40. 
D. Thallus continutus green or reddish; filres parallel, 
diverging from the base; bark chalklike or hairy. Zonaridez. 
Thallus ribless, fanshaped ........ -... ZONARIA. 41. 
Thalhis ribless, forked. grees eee Dicryota. 42. 
Thallus ribbed, forked ........... DicTyopreris. 43. 
E. Thallus continuous, cellular, green becoming white ; 
bark smooth ; sporidia scattered, immersed. Ulvoidee. 
Thallus compressed; sporidia prominent 
ASPEROCOCCUS. 44. 
Thallus membranaceous, flat; sporid.immersed Uva. 45. 
Thallus tubular; sporidia immersed ScyrosiPHon. 46. 
Thallus threadlike}solid «23.00 000.008: PaLMELLA. 47. 
Dhatlasitlatsyhlestiye:: .. .....</y}esapsvensmoreroe MERRETTIA. 48. 
Thalli globular or ovate, aggregated ..... Onrvia. 49. 
F. Thallus continuous, gelatinous, fleshy, cellular ; spori- 
dia in many immersed beaded filaments. Linkidee. 
Thallus long; sporidia elliptic...... Carroporus. 51. 
Thallus bullated ; sporidia globular ...... Nostoc. 50. — 
G. Thallus continuous, gelatinous, cellular, smooth, olive 
becoming black ; sporidia scattered, immersed. Alcyonidee. 
Cells 6-edral, long; marine....... ALCYONIDIUM. 52. 
Cells long, regular, radiating ........ EPHIDATIA. 53. 
Cells iwmneoularse marshy... cgie «cic < paves SPONGILLA. 54. 
H. Thallus continuous, spongy, gelatinous, formed of in- 
terlaced fibres or spicula yellowish ; sporidia scattered, im- 
mersed. Spongidiz. 
Thallus branched, solid; fibres entangled .. TupuHa. 55. 
Thallus tubular; fibres entangled ........ ScyPHA. 56. 
Thallus not branched; fibres entangled .. Sponeia. 57. 
Thallus orbicular; fibres radiatel ...... TEvuya. 58. 
