678 C. SKOTTSBERG 



The association may continue into the middle httoral, accompanied by 

 colonies of Scytothajnnus and other brown algae. We are perhaps entitled to 

 distinguish this zone as a Choridriella-ScytotJiamnus Ass. 



iJlva rigida Ass. U. rigida is associated with Etitcroinorp/ia or forms more 

 or less pure societies in the lower littoral (St. 36 b). In St. 40 a, on very 

 exposed coast, patches of Ulva rigida occurred with carpets of Gratcloupia sub- 

 simplex. Unfortunately, this is the only intertidal community observed by me 

 in Masafuera. 



Enteroniorpha iiitestiiialis Ass. A more or less pure community occurs as 

 a narrow belt in rock pools of the upper littoral, exposed at low tide (St. i), 

 followed by a Polysiphouia Ass., and on coarse sand in sheltered depressions. 



Enteroniorpha-Chactopliora cDitoniiiia Ass. Obser\-ed once, on coarse black 

 sand (St. 36 a). 



GlossopJiora Ass. G. Kunthii occasionally abounds along low-water mark 

 (St. 38 b). 



Chactoniorpha firi)ia-Splachnidiujii Ass., with a more or less developed 

 bottom synusia of LithopJiylhan feritandesianiDH, covers the lower littoral in 

 Bahi'a del Padre, but was not observed elsewhere. Where the specimens of 

 SplacJniidiuui taken by the Ha.sSLER expedition came from I do not know. 

 Chaetouiorplia firuia was also dredged in deeper water. Bahia del Padre is the 

 only station visited where the intertidal belt has a wide horizontal extension and 

 where the breakers are checked before hitting the unco\ered area, which may 

 have something to do with the luxuriance of the vegetation (comp. plate 54). 

 SplachnidiuDi, with its excellent attachment and tough, cylindrical thallus, ought 

 to be quite surf-resistant. CliaetoinorpJia firuia forms 5 — 6 cm long, erect and 

 densely packed, rather rigid tubes of a light green colour. This association 

 corresponds to the Iridaea Ass. and also to the Adejiocystis-CJiIoropliyccae 

 Ass. of south Chile and the Subantarctic region (Skottsberg, 1. c), and also 

 to the association of Fucaceac characteristic of temperate and cold seas, but not 

 developed on the Chilean coast. There is, however, no member of the Fucaceac 

 found at Juan Fernandez. 



Codiuj)i-Lithophylluui (or Lithothamnion) Ass. is developed along low-water 

 mark and in pools, where a fairly rich flora with Dictyotaceae, various RJiodo- 

 pJiyceae, etc. occurs. The community corresponds to the principal sublittoral 

 association described below. 



Sublittoral associations. 



Our knowledge of the deep-water flora is probably far from complete. 

 Three of the known sublittoral algae, Hydroclathus clathratus (dredged in 15 

 — 20 fathoms), Papenfussiella Moseleyi and Nemastoma foliaceum, are not in my 

 collection. Several other species have been observed a single time, and some are 

 known from beach deposits only. 



No catch was made in a lesser depth than 10 m. In temperate and cold 

 waters the region between o m and 10 m is the richest, but whether this is the 



