140 MES. A. WEBEE-VAN BOSSE ON THE 



concerned, and reproductive organs were not to be found. The cells of tlie 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 jP. polymorj^ha had lost in 

 all the specimens I have seen. 



I conclude that f . Gardineri is a deep-water form of P. ^olymorpha. 



Subgen. Ethelia, n. subg. 



Mesothallus filis rectis aut ramosis, sinuatis, utroque latere fila perithalli emittens 



5. Peyssonnelia bieadiata, n. sp. 



Thallo per substratum extento, tantum hie illic adhserente, coriaceo, rubro, rotundo, 

 diametro 2 ad 3 centimetrum, constante e mesothallo et perithallo. Mesothallo 

 constante e filis ramosis, sinuatis, parva flabella efiicientibus. Perithallo constante 

 e filis sursum et deorsum directis. Perithallo summo diviso in partem inferiorem 

 obliquam, cellulis magnis, et in partem superiorem erect am, hie illic zonatam, 

 cellulis parvis. Organis fructificationis ignotis. 



Seychelles, 31 fms. ; dry specimen. 



Distribution. Malay Archipelago. 



I 



A small but characteristic specimen. 



Among the algae from Saya de Malha there are several specimens that I believe belong 

 to the genus Pei/ssonnelia, but they are unfortunately barren. They have much in 

 common with the I*eyssonneU(B of the Ethelia-groui^, for they have a mesothallus that 

 gives off branches both in a downward and upward direction (Pi, 14. fig. 36). They are 

 furthermore much calcified, hard as stone, and attached to bits of coral. 



But besides these features found among the JSthelia-grou^, the Feyssonnelice from 

 Saya de Malha are characterized by long filaments (PI. 14. fig. 37) almost free from each 

 other and covered by a layer of pectic substance, which colours red with ruthenium. 

 The filaments are like those we find in the sori of other JPeyssonnelice, 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 Ralfsiacese are covered 

 by filaments, and it appears probable that we have here something analogous amongst 

 the JPeyssonnelicB ; but until the reproductive organs are discovered it is difficult to 

 speculate as to these structures. A doubt still 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. 



Crtjoriopsis, Dufour 

 1. Cruoriopsis cruciata, Dufour. 



Dufour, Elenc. Alg. Lig. p. 35, after De Toni, 

 De Toui, Syll. Alg. vol. iv. sect. iv. 1905, p. 1689. 



Saya de Malha ; dry specimen on Xldotea, 



