Leafweed. Fronds cylindrical; branched stalks which expand into rigid, membranaceous, simple or cleft, wedge-shaped laminæ; laminæ bear leaflets on their edges or on their surface; spores in masses form projections on the surface, or are on stalks at the summit; color dark red. Found washed ashore from New York northward. [pg082] ^P. membranifolia.^ Several stems rise from same disk; branches expand into wedge-shaped, cleft or forked laminæ; lobes bear on the summit other laminæ or leaflets divided in the same manner. ^P. Brodiæi.^ Stem less branched and leaf-expansions broader and larger than in /P. membranifolia/; laminæ wedge-shaped and deeply lobed. (Plate XIX.) GENUS ^Sternogramme^ ^S. interrupta.^ Frond a thin membrane repeatedly forked, widely spreading, divisions one fourth to one half of an inch wide; fertile plants have the spores arranged in an interrupted line through the center of the segments resembling a midrib; frond two to eight inches high; bright red. It is found on the California coast. The illustration shows a plant on which the hydroid /Sertularia pumila/ is growing. (Plate XIX.) GENUS ^Gymnogongrus^ ^G. Norvegicus.^ Frond two to four inches high, thin but leathery in substance, flat, narrow, divided in a regular forking manner; spreading ends of terminal forks obtuse; axils rounded; spores form spherical masses in the upper segments, and project on both sides like hemispheres. It resembles a simple form of /Chondrus crispus/, but is more delicate. The color is red or purple. This species is found in deep tide-pools from New York northward. (Plate XIX.) GENUS ^Ahnfeldtia^ ^A. plicata.^ Frond coarse, stem-like filaments, stiff, wiry, irregularly and profusely branched; sometimes regularly forked and upper segments equal; entangled; six to eight inches long; tufts several inches in diameter; dark purple or black. Specimens long exposed on the beach are faded to white. It is very common from New York northward. (Plate XIX.) GENUS ^Callophyllis^ ^C. variegata.^ Deeply cleft, wide-spreading, flat, membranaceous frond; all parts notched more or less angularly; color dark to bright red; spores form hemispherical warts on surface. Some varieties differ from this one in having long and narrow, and others in having short and broad segments. It is a beautiful and common alga on the Pacific coast, resembling /Euthora/ of the eastern coast. (Plate XX.) ^C. laciniata.^ Frond deeply cleft; segments wedge-shaped. It is found on the Pacific coast. (Plate XX.) [Illustration: PLATE XIX. Phyllophora Brodiæi. Sternogramme interrupta. Gymnogongrus Norvegicus. Ahnfeldtia plicata.] [Illustration: PLATE XX. Callophyllis variegata. Callophyllis laciniata. Iridæa. Cystoclonium cirrhosa.] GENUS ^Iridæa^