478 ETHEL 8. BARTON ON THE MARINE ALG 
bus (10 vel plus) cellularum composita ; unius strati infra medium 
positi cellulis maximis rectangulis protoplasma intense coloratum 
continentibus ; stratis ceteris dimidio tenuioribus, paginam 
superiorem versus cellulis partitione verticali plus et plus sub- 
divisis ; pilis vel numerosis congestis ex areolis superficialibus, 
vel parvis ex cryptostomatibus minutis ortis ; sporavgiis nullis. 
The absence of fruit makes it impossible to be sure of the 
exact position of this alga, which differs in certain details from 
other species of Ralfsia. In surface view the uppermost layer 
is seen to consist of small cells, arranged in long, continuous 
bands, separated by a very thin, translucent line. Each band is 
divided transversely into rows of from 2-4 cells (Pl. 13. fig. 2). 
The moniliform rhizoids form a thick mass below the flat thallus 
(Pl. 13. figs. 3 & 4), and the cells of the thallus arise in vertical 
lines from the very base. About the middle of the thallus, as 
seen in transverse section, is a single horizontal row of large, 
rectangular, deeply-coloured cells, and the cells of the 2 or 3 
adjacent horizontal layers on each side correspond in width with 
these large cells, but are about half the depth (Pl. 13. fig. 3). 
The uppermost layers are composed of small cells, and from these 
arise here and there patches of hairs. Small fascicles of hairs 
often arise from minute cryptostomata situated in the same 
superficial or uppermost layer. 
14, LirBMannta LaccaDIvaRuM, n. sp.; fronde inferne later- 
aliter parce ramosa, ramis simpliciusculis tenuibus cylindraceis, 
sepe flexuosis, sensim attenuatis, adscendentibus, 2 mm., rarius 
3 mm., lata. Sporangia unilocularia hucusque ignota. Sporangia 
plurilocularia lanceolata, 55-75 » long. x 15p lat., e cellulis 
filorum periphericorum inflatis basalibus orta, in pedicellis sim- 
plicibus vel furcatis terminalia. Fila peripherica longissima 
flexuosa, inferne semi-moniliformia cellulis basalibus pluribus uni- 
lateraliter inflatis, superne longe cylindracea. (Pl. 13. figs. 5-8.) 
Hab. Minikoi, Laccadive Islands. Found only on the upper 
(i. e. inner) terrace of the reef to the east of the island. Rooted 
in sand. On July 26th, 1899, it was timed as being exposed to 
the air for 43 hours at low tide. 
This plant resembles L. Harveyana, J. Agh., in its manner of 
branching, but is much more slender. A transverse section of 
the two plants shows at once the difference in structure. In 
L£. Harveyana the peripheral filaments are grouped in fascicles, 
