8 9 



If this conclusion is true a great number of species have to be sunk and can only be, 

 according to smaller or greater deviations, retained as varieties or forms. 



Working out the Amphiroae of the Siboga Expedition principally with reference to the 

 structure of the node, I found that the collection contained the following species : 

 i. A. fragilissima f. cuspidata and f. cyathifera. 



2. A. anastomosans, a new species nearly related to the former. 



3. A. foliacea f. typica f. nobilis. 



4. A. anceps. 



5. A. Boiverbankii. 



6. A. ep lied ra ca . 



7. A. canaliculata. 



8. A. c ras sa, f. Godcffroyi and f. mini ma. 



With the exception of A. crassa the cortical layer takes part in the formation of the 

 node of all these species. The structure of the node is in all specimens the same in each 

 species. In A. anceps the node shows a tendency to deviations, as did also the regularity 

 wherewith long and short cells alternated in the central strand of the joint. This shows that 

 A. anceps is a highly variable plant, vvhereas in A. ephedraea for instance the structure 

 of the node and the regularity wherewith long and short cells alternate is much more constant. 

 Since however the great variability of which the genus Amphiroa is capable, is amply shown 

 by A. foliacea, I resolved to unite in one species all Amphiroae the nodes of which were 

 essentially the same as the node of the type specimen of A. anceps. 



Whether this conception of the species is right or wrong can only be made out by 

 careful study on the spot where these algae grow ; it may at least be a help for the present, 

 and the study of the node will prevent various genera from being mistaken for one another, as 

 was the case in some collections I have been able to study. 



I will now proceed to a systematic description of each species contained in the Siboga 

 collection. 



1. Amphiroa fragilissima (Linn.) Lamx. PI. XIV, hg. 5. 



Corallina fragilissima Linné, Syst. nat. ed. 12, vol. I, p. 1305. Ellis et Solander. Zooph. 



p. 123, t. 21, fig. 9. 

 Corallina rigens Pallas, Elench. Zooph. p. 429 fide Areschoug. 

 Amphiroa fragilissima Lamouroux, Pol. flex. p. 298. 



Amphiroa debilis Kutzing, Spec. Alg. p. 700. Tab. Phyc. t. 8, pi. 39, 40. 

 Corallina cuspidata Ellis et Solander, Zooph. p. 124, t. 21, fig. 9/. 

 Amphiroa cuspidata Lamouroux, Pol. flex. p. 300. 



Amphiroa cyathifera Lamouroux in Freycinet, Voy. de 1'Uranie, Zool. par Quoy et Gaimard p. 627. 

 Amphiroa fragilissima Lamouroux, Areschoug in Agardh, Spec. Gen. et Ord. Alg. t. 2, 185 1, p. 53 1. 



f. fragilissima . 



Amphiroa fragilissima Lamx. 



Stat. 34. Labuan-Pandan. 



Stat. 60 and 303. Haingsisi, Island Samau. 



Stat. 71. Makassar. 



SIBOGA-EXPEDIT1E LXI. 12 



