PL cell. aph. 1. HYDROPHYTE. 11. Codium. 29S 
2. Codium dichotomum . Two-forked codium . 
nearly cylindrical, threadlike, forked. 
Spongia dichotomos teretifolin, viridis, Raii Syn. 29, 3. 
Spongia dichotomos compressa ex viride splendens, Raii Syn. 29,4. 
Fucus tomentosus, Hudson FI. Angl. 584 ; Engl. Dot. 7 17. 
Fucus fungosus, Des Font. FI. All. 2,428. 
Spongidium dichotomum, Lamouroux Essai. 
Codium tomentosum, Stackfi. in Agardh Disp. 
South-west coast ; perennial; June and July. 
Trunks from a dilated base, many, 6 inches long; fork 
obtuse-angled; branches even-topped, blunt at the tip. 
0. marginifer. Mass two-forked, beset all over with, 
short, horizontal, forked segments. 
E. Diatomideje. Thallas threadlike, tubular, flat, 
jointed, sometimes united parallelly through their whole 
length ; joints often separating but still cohering at the 
angles; spordia granular, enclosed in the joints — often pa- 
rasitic on marine plants, forming when dry a shining white 
crystalline crust. 
XI L 12. FRAGILARIA. Lyngbye. Breaking-zip . 
Thallas threadlike, jointed, flat, not branched, very 
brittle; joints without any band, separating but cohering 
by one of their corners; sporidia granular, enclosed in the 
joints. 
1. Fragilaria striatula. Streaked breaking-up . 
Threads yellowish green, compressed, even ; joints shorter 
than broad, in pairs, regularly streaked tranversely. 
Conferva striatula, Engl. Bot. 1928. 
Fragilaria striatula, Lyngbye Hydr Dan. 183. 
On rocks and marine plants ; April. 
Threads about a tenth of an inch long. 
2. Fragilaria tceniaformis, Tapeworm breaking-tip . 
Threads compressed, pale green, even ; joints three times 
broader than long, obscurely variegated. 
Conferva tseniaeforinis, Engl. Bot. 18S3. 
Diatoma ? taeniceformis, Agardh Disp. 35. 
On marine plants ; February. 
Tufts a twelfth of an inch long. 
