maeijS'E alg.^ of the *sealaek' expedition. 135 



thick, the transverse membranes of the succeeding segments within are plainly Tisihle, 

 owino- to the fact that the central strand consists of a large number of cells of equal 

 leno-th. The segments are short, and this fact gives, whenever the apex of a shoot is 

 pushed aside, the impression that the main axis is divided into three branches. Careful 

 examination will, however, show that this impression is erroneous, being brought about 

 by the displaced shoot, its first branch— the new shoot— and its second branch standing 

 very close together, owing to the short segments and the congenital growth of the first 



two segments. 



My plants are barren : J. Agardh, however, described the stichidia, which he stated 



were like those of Dasya and bore verticillately developed tetraspores partially uncovered 



ft 



on the outside. 



AmpUshetema has received its name* on account of the dilUculty experienced in 



to it its true systematic position . It has characters in common with several 



giilXi^ 



genera of Uhodomelacese and also with Melanothamniis, Born, et Palk., a genus of 

 uncertain position so long as the organs of fructification remain unknown. 



With Streblocladia, AmpUshetema agrees in the regular alternating mode of mono- 

 podial and sympodial growth ; with 3Ielanoihammts and JRndosiphonia in the numerous 

 secondary pericentral cells of equal length ; with Ueferosiphonia in the dorsi- ventral 

 organization of its branches ; and with Dasj/a in the structure of the stichidia. 



The association of all these characters in one genus makes me inclined to consider 

 AmpUshetema as an old form of Uhodomelacese which existed before the genera that 

 have now developed one or more of the characters— in our new genus still blended 

 too>ether— in their own special way and to the exclusion of the other cliaracters. 



DiCTYUHUS, Bory. 



* 



1. DiCTTTJUUs pruPUHASCENS, Bory. 



Bory de St. Vincent, in Belanger, Voy. Indes orient, p. 170. 

 Falkenberg, Die Rhodomelaceen, 1901, p. 675. 

 De Toni, Syll. Alg. vol. iv. sect. in. 1903, p. 1173. 



Saya de Malha, 55 fms.; dry specimen. 



Coetivy, reef ; dry specimen and in alcohol (fragment). 



Cargados Carajos* 30 and 47 fms. ; dry specimen and in alcohol 



Amirante, 30 fms. ; in alcohol. 



Chagos Archipelago, Solomon Isl., 22 fms. ; in alcohol 



Disfrib 

 pelago. 



Cape Comorin; Coast of India; Mauritius; Ceylon; Malay Archi- 



Fam. CEEAMIACE^. 

 Griffithsia, C. Agardh. 



1. Griffitiisia spec. 



Amirante. 20-25 fms. ; in alcohol 



Only a small fragment, but with the characteristic tetraspores of the g 



m 



iLfx<l>i<TlV,rniia, controversy, a point in dispute. 



