F. Borgesen: Rhodophyceæ of the Danish W. Indies. 185 



characteristic of this species: the swollen padlike ends of the 

 joints, pointed out very clearly in Linné's short diagnosis which 

 runs^): "C. dichotoma, articulis fdiformibus divaricatis, apice 

 basique latioribus" and described later on by Lamouroux in 

 Hist. d. Polyp. Corallig. flexibl., p. 298 (first quoted by Harvey) 

 in this way: "articulations cylindriques avec un renflement en 

 forme de boulet å leurs extrémités". In Ellis and Solander's 

 description of their Corallina fragilissima (in Nat. Hist. Zoophytes 

 1786, p. 123, pi. 21, fjg. d) this character is not mentioned. Their 

 diagnosis of the species runs verbally : "Corallina dichotoma, 

 articulis cylindricis, æqualibus lævibus ramis erectis". This dia- 

 gnosis agrees perhaps best with Amph. rigida the padlike swollen 

 ends of the joints being not mentioned, but the upper bifurcate 

 ends of the joints characteristic of this species are neither 

 mentioned, and if we examine their figure the nodes except one 

 are drawn at the dichotomy. As an examination of Ellis and 

 Solander's specimens is not possible, their collections, as men- 

 tioned earher (comp. p. 89), most probably not existing any 

 longer, it seems to me the best course to regard Amph. fragilissima 

 and Amph. rigida in the sense of Lamouroux and this the more 

 so, as Linne's short, but striking diagnosis of Corallina fragilissima 

 does not leave any doubt as to the plant he had before him. 



This species has been found only once. It was growing in 

 shallow water between Cymodocea manatorum and other sea- 

 grasses in a place somewhat sheltered by coral reefs. 



St. Croix: Rust up Twist. 



Geogr. Distrib. : Mediterranean Sea, West Indies, Japan. 



2. Amphiroa fragilissima (L.) Lamx. 



Lamouroux, I. V. F., Histoire des Polypiers corallig. flexibl. vulg. 

 nomm. Zoophytes. Caen 1816, p. 298. Areschoug, I. E., in J. Agardh, 

 Spec. Alg., vol. 2, pars 1, 1851, p. 531. Weber- van Bosse, A. and M. Foslie, 

 The Corallinaceæ of the Siboga-Expedition, Leiden 1904, p. 89, pi. XVI, 

 figs. 1, 2, 5 (ubi synomyna pluria). KOtzing, F., Tabulæ Phycologicæ, 

 vol. 8, pi. 39, flg. 1. 



Corallina fragilissima L., Systema nat., ed. 12, vol. 1, p. 1305). Ellis, 

 J. and D. Solander, Zoophytes 1786, p. 123, pi. 21, fig. d? (comp, remarks 

 above). 



Amphiroa debilis Kiitz., Spec. Algarum, 1849, p. 700. Harvey, W. H., 

 Nereis Bor.-Am., Part II, 1853, p. 86. 



^) LiNNÉ, Systema Naturae. Editio duodecima reformata. Holmiæ 1767. 

 Tom. I, Pars II, p. 1305. 



