286 PERCY SLADEN TRUST EXPEDITION 
no. 8 are more slender, while the alga from Coetivy Reef is very much like specimens in 
Kiitzing’s herbarium and named L. obtusa var. racemosa. The specimens from Egmont 
Reef are rather short, but they probably represent young plants. They show the charac- 
teristic branching of the species, and all the branches have blunt truncated apices. 
3. LAURENCIA PAPILLOSA (Forsk.), Grev., f. AUSTRALICA, in herb. Kiitzing. 
Aldabra, reef; dry specimen. 
Seychelles, Long Island ; dry specimen. 
Coetivy, reef. 
Distribution. New Caledonia. 
I have been in doubt about these algze for they differ from typical specimens of 
LL. papillosa. They come near to two barren specimens from New Caledonia in 
Kiitzing’s herbarium. Mr. Stanley Gardiner’s specimens being also barren, I abstained 
from giving a diagnosis. 
4, LAURENCIA SPINULIFERA, Kitz. 
Kiitzing, Tab. Phye. Bd. xv. 1865, tab. 61, p. 22. 
Chagos Archipelago, Diego Garcia, reef; in alcohol. 
Distribution. Indian Ocean. 
The specimens come near to some forms of L. obtusa, but they are distinguished by 
their small size. I think that until all the forms of ZL. obtusa from the Hast Indies are 
better known, we may retain Kiitzing’s species. 
5. LAURENCIA PYGMHA, n. sp. (Plate 16. fig. 6.) 
Fronde tereti, filiformi, tenui, circa 1 cm. alta, pulvinatim ceespitosa, intricata ; ramis 
primariis decumbentibus, secundariis erectiusculis; ramulis clavatis, truncatis. 
Ramis primariis usque ad 250 n» erassis, ramis secundariis et ramulis tetrasporiferis 
100-150 u crassis. Cystocarpiis et antheridiis non visis. 
Chagos Archipelago, Diego Garcia, reef; in alcohol. 
Laurencia pygmea is distinguished by its size, which is indeed dwarf for a Lawrencia. 
It grows in tufts, and the alcohol material looks as if it had grown on stones or shells 
and had been cut off with a knife. The thallus consists of decumbent branches—I have 
seen no rhizoids—which give off suberect ascending ones; these are branched irregularly. 
Sometimes the ramuli are subopposite, sometimes subverticillate or even single. They 
are always slender, and not particularly short as are the ramuli of LZ. pannosa, Zan. 
From this plant, Z. pygm@a may also be known by its thalli, which, though intricate, 
are easily teased out under a pocket-lens, whereas in the case of L. pannosa this cannot 
be done, according to Zanardini, without damaging the frond. The mode of branching 
reminds me of L. obtusa, but the thallus is very slender, the main branches having a 
diameter of 200-250 » and the side-branches and tetrasporiferous ramuli from 100-150 p. 
Characteristic of this small alga are the swollen light-reflecting lateral membranes of 
the central cells. From Z. indica, Hauck, it is easily known by its small size. 
