304 PERCY SLADEN TRUST EXPEDITION 
concerned, and reproductive organs were not to be found. ‘The cells of the f. Gardineri 
are perhaps, on the whole, somewhat smaller than those of the type, and seen from above 
f. Gardineri is covered by a smooth peripheral layer, which P. polymorpha had lost in 
all the specimens I have seen. 
I conclude that f. Gardineri is a deep-water form of P. polymorpha. 
Subgen. Ernpnia, n. subg. 
Mesothallus filis rectis aut ramosis, sinuatis, utroque latere fila perithalli emittens. 
5. PEYSSONNELIA BIRADIATA, 0. sp. 
Thallo per substratum extento, tantum hic illic adheerente, coriaceo, rubro, rotundo, 
diametro 2 ad 3. centimetrum, constante e mesothallo et perithallo. Mesothallo 
constante e filis ramosis, sinuatis, parva flabella efficientibus. Perithallo constante 
e filis sursum et deorsum directis. Perithallo summo diviso in partem inferiorem 
obliquam, cellulis magnis, et in partem superiorem erectam, hic illic zonatam, 
cellulis parvis. Organis fructificationis ignotis. 
Seychelles, 31 fms. ; dry specimen. 
Distribution. Malay Archipelago. 
A small but characteristic specimen. 
Among the algze from Saya de Malha there are several specimens that I believe belong 
to the genus Peyssonnelia, but they are unfortunately barren. They have much in 
common with the Peyssonnelie of the Hthelia-group, for they have a mesothallus that 
gives off branches both in a downward and upward direction (PI. 18. fig. 36). They are 
furthermore much calcified, hard as stone, and attached to bits of coral. 
But besides these features found among the “thelia-group, the Peyssonnelie from 
Saya de Malha are characterized by long filaments (PI. 18. fig. 37) almost free from each 
other and covered by a layer of pectic substance, which colours red with ruthenium. 
The iilaments are like those we find in the sori of other Peyssonnelie, but in the new 
plants they are not confined to sori alone, but cover the whole upper surface. Although 
I made sections through all parts of the thallus, I could find no trace of fructification. 
We know that the fronds of Stragularia species amongst the Ralfsiacezee are covered 
by filaments, and it appears probable that we have here something analogous amongst 
the Peyssonnelie ; but until the reproductive organs are discovered it is difficult to 
speculate as to these structures. A doubt stiil lurks in my mind whether, after all, 
these filaments may not belong to an encrusting parasitic alga; but it is well worth 
while to call attention to these specimens. 
Cruortopsis, Dufour. 
1. Cruortiopsis crucIATA, Dufour. 
Dufour, Elenc. Alg. Lig. p. 35, after De Toni. 
De Toni, Syll, Alg. vol. iv. sect. rv. 1905, p. 1689. 
Saya de Malha; dry specimen on Udotea. 
