A REVISED LIST OF CORALLINE. 13 



= Amp. setacea Kutz. Spec. p. 700. 



= Amp. similis Sond. (sec. Weber 1. c. p. 84.) 

 Corallina Chara Lamx. Mem. Mus. I. p. 240. 

 Cor. radiata Lamx. Mem. Mus. I. p. 240. 



This genus is easily distinguished from the others by having 

 verticillate ramuli which start from genicula and not from articuli. 

 The articuli are exclusively cylindrical, varying in their length 

 according to the position in a frond and to the species. In some 

 species, both extremities of the articuli bulge out, owing to the 

 secondary development of the circumgenicular cortex ; and in 

 some species the verticillate ramuli are slightly curved upward 

 and inward. 



The conceptacles are, as far as I could observe from the 

 accessible material, generated from the medullary cells. The 

 diameter of the conceptacles is very large when compared with 

 that of the ramuli ; in Metagoniolithon stelligerum the former is 

 subequal to the latter. This circumstance, no dobut, forces con- 

 ceptacles to stai>t from the deep places in the medulla. 



The species under this genus are characterised by much 

 elongated genicula. In Metag. stelligerum the length of a matured 

 geniculum often attains more than twenty times its breadth, and 

 the greater portion of the racliis is formed by the genicula. 

 These genicula, quite strange in comparison with those of plants 

 belonging to other genera, can send out the verticillate ramuli 

 around a certain region. No ramuli is found starting directly 

 from an articulus. This peculiarity, together with the medullary 

 origin of the propagating cells, is enough to detach the present 

 group from the genus Amphiroa and to place it under a new 

 one. In my former paper I made a preliminary announcement 

 of this matter. A few months later, Madam Weber, evidently 



