Pl.cell.aph. 1. HYDROPHYTA. 11. Codium. 298. 
2. Codium dichotomum. Two-forked codium, 
. Mass nearly cylindrical, threadlike, forked. 
Spongia dichotomos teretifolia, viridis, Rati Syn. 29, 3. 
Spongia dichotomos compressa ex viride splendens, Rati Syn, 29, 4. 
Fucus tomentosus, Hudson Fl. 4ngl. 584; Engl. Bot. 717. 
Fucus fungosus, Des Font. Fl. Atl. 2, 428. 
Spongidium dichotomum, Lamouroux Essai. 
Codium tomentosum, Stackh.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. 
8. marginifer. Mass two-forked, beset all over with 
short, horizontal, forked segments. 
E. Dratomipex. Thallus 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. 
XID. 12. FRAGILARIA. Lyngbye. Breaking-up. 
Thallus threadlike, jointed, flat, not branched, very 
brittle; jovzts 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; join/s shorter 
than broad, in pairs, regularly streaked tranversely. 
_ Conferva striatula, Engl. Bot. 1928. 
Fragilaria striatula, Lyngbye Hydr Dan. 1&3. 
On rocks and marine plants; April. 
Threads about a tenth of an inch long. 
2. Fragilaria teni@formis. Tapeworm breaking-up. 
Threads compressed, pale green, even; joints three times 
broader than long, obscurely variegated. 
Conferva tenixformis, Engl, Bot. 1883. 
Diatoma? tznivformis, dgardh Disp. 35. 
On marine plants; February. 
Tufts a twelfth of an inch long. 
